Liquid droplet ejection apparatus, method of manufacturing electroptical device, electrooptical device, and electronic apparatus

ABSTRACT

A method of drawing on a workpiece by ejecting functional liquid thereon while relatively scanning the workpiece and an ejection head is provided. The method comprises the steps of: a first scanning for drawing in a plurality of first areas along a scanning direction; and a second scanning for drawing in a second area between the plurality of first areas drawn in by the first scanning.

This application is a continuation of U.S. patent application Ser. No.12/255,905 filed on Oct. 22, 2008 which is a divisional of U.S. Pat. No.7,455,388 issued on Nov. 25, 2008. This application claims the benefitof Japanese Patent Application No. JP2004-142449 filed May 12, 2004 andJP2004-300770 filed Oct. 14, 2004. The disclosures of the aboveapplications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a liquid droplet ejection apparatus forejecting (or discharging) function (or functional) liquid droplets ontoa substrate so as to image (or draw) on the same, while moving aplurality of color-dependent function liquid droplet ejection headshaving a plurality of corresponding colors of function liquid introducedtherein, relative to the substrate. This invention also relates to amethod of manufacturing an electrooptical device, an electroopticaldevice, and an electronic apparatus.

2. Description of the Related Art

In a known liquid droplet ejection apparatus for use in manufacturing acolor filter, while moving color-dependent inkjet heads (function liquiddroplet ejection heads) having introduced therein three kinds of ink(function liquid) of R (red), G (green), and B (blue) colors,respectively, relative to a glass substrate having a black matrix (aplurality of pixel areas) formed thereon, an imaging process isperformed by ejecting and landing ink droplets on the black matrix onthe basis of a color arrangement pattern composed of the three colors.In such a liquid droplet ejection apparatus, in order to accuratelyeject ink droplets onto the black matrix, amounts of positionaldeviation of an X-Y stage (an X-axis table and a Y-axis table) moving asubstrate relative to the inkjet heads are measured, and the amounts ofpositional deviation are corrected.

However, in an imaging operation of the liquid droplet ejectionapparatus, even when the amounts of positional deviation are corrected,it is difficult to exactly or accurately eject ink onto the black matrixdue to undesirable speed variations of the X-Y stage, a curved flyingtrajectory of ink, and so forth. Especially, when three kinds of ink ofR, G, and B colors are simultaneously ejected (through a common mainscanning operation), ink droplets not exactly ejected in mutuallyadjacent pixel areas cause ink of different colors to be mixed with eachother on the substrate, resulting in deteriorating quality of amanufactured color filter.

SUMMARY OF THE INVENTION

Accordingly, it is an advantage of this invention to provide: a liquiddroplet ejection apparatus having a structure in which, when functionliquid droplets of a plurality of colors are simultaneously ejected andlanded on a substrate, function liquid droplets of different colors areprevented from mixing with each other even when the function liquiddroplets are not exactly landed in respective pixel areas; a method ofmanufacturing an electrooptical device; an electrooptical device; and anelectronic apparatus.

According to one aspect of this invention, there is provided a liquiddroplet ejection apparatus for ejecting function liquid droplets so asto be landed in a plurality of pixel areas formed on a substrate on abasis of a color arrangement pattern composed of a plurality of colors.The function liquid droplets are ejected by moving, relative to thesubstrate, a plurality of color-dependent function liquid dropletejection heads having a plurality of corresponding kinds of functionliquids introduced therein. The apparatus comprises: a plurality ofcarriage units, each having the plurality of color-dependent functionliquid droplet ejection heads placed on a corresponding carriage; anX-axis table having the substrate thereon and moving the substrate in anX-axis direction as a main scanning direction; a Y-axis table for movingeach of the plurality of carriage units in the Y-axis direction; andcontrol means for controlling each of the function liquid dropletejection heads, the X-axis table and the Y-axis table. The plurality ofcolor-dependent function liquid droplet ejection heads of each of thecarriage units is arranged such that a plurality of color-dependentpartial imaging lines, each formed by a plurality of ejection nozzles,are connected to one after another in a predetermined order in theY-axis direction so as to make up a single divided imaging line. Thecontrol means performs the imaging process by repeating a main scanningoperation for driving each of the function liquid droplet ejection headsin synchronization with the substrate moving in the X-axis direction anda sub-scanning operation for moving each of the function liquid dropletejection heads in the Y-axis direction through the carriage unit byabout each of the partial imaging lines.

In this case, the color arrangement pattern is preferably of any one ofstripe, mosaic, and delta arrangements.

According to the above arrangement, the plurality of color-dependentpartial imaging lines are continuously connected to one another in apredetermined order (for example, in the order of R, G, and B) in theY-axis direction and do not overlap with one another in the X-axisdirection, whereby function liquid droplets of mutually different colorsare not ejected and landed in respective pixel areas lying mutuallyadjacent in the X-axis direction through a common main scanningoperation. Hence, even when function liquid droplets of different colorsare respectively landed on a part of a bank section between pixel areaslying mutually adjacent in the X-axis direction, both function liquiddroplets are ejected and landed through mutually different main scanningoperations; hence, function liquid droplets ejected through a first mainscanning operation are dried to a certain extent at the time when otherfunction liquid droplets are landed by a second main scanning operation,whereby both function liquid droplets do not mix with each other.Accordingly, function liquid droplets of different colors are reliablyprevented from mixing with each other between the pixel areas lyingmutually adjacent also in the X-axis direction. Also, since functionliquid droplets of a plurality of colors are simultaneously ejected andlanded, imaging can be effectively performed with a single liquiddroplet ejection apparatus. In addition, when function liquid of asingle color is introduced in the plurality of droplet ejecting headshaving the above-descried structure, imaging can be effectively made bymoving the droplet ejecting heads by an imaging line without moving themby each partial imaging line in a sub-scanning operation.

When a color filter is manufactured, while three kinds of functionliquid of R, G, and B are usually used as function liquid of a pluralityof colors, four kinds of function liquid of three colors of R, G, and Bcolors and an additional C (cyanic) or E (emerald) color may be used soas to improve a color reproduction property. As a matter of course,function liquid of another combination of colors or of other colors maybe used. Pixel areas are defined such that function liquid droplets of aplurality of colors (for example, three colors R, G, and B) are landedin the respective pixel areas. In this case, three pixel areasrespectively having an R-function liquid droplet (i.e., function liquiddroplet of red color), a G-function liquid droplet (i.e., functionliquid droplet of green color), and a B-function liquid droplet (i.e.,function liquid droplet of blue color) landed therein make up aso-called pixel.

It is preferable that each of the carriage units has the plurality ofcolor-dependent function liquid droplet ejection heads placed on thecarriage and that the plurality of color-dependent function liquiddroplet ejection heads of each of the carriage units be arranged suchthat the plurality of color-dependent partial imaging lines, each formedby the plurality of ejection nozzles, are repeatedly connected one afteranother in a predetermined order in the Y-axis direction so as to makeup a single divided imaging line.

According to the above arrangement, a plurality of the partial imaginglines of respectively different colors are repeatedly connected oneanother in the Y-axis direction in a predetermined order (for example,in the order of R, G, B, R, G, B, R, G, and B colors) so as to make upthe divided imaging lines. Hence, each partial imaging line is shorterthan one of the partial imaging lines of respective colors, which areconnected one another in the Y-axis direction in a predetermined orderso as to make up the divided imaging lines (e.g., of R, G, and Bcolors), thereby leading to a shorter moving distance of each functionliquid droplet ejection head, and thus resulting in a shorter time of asub-scanning operation.

In this case, when function liquid droplets ejected in two of the pixelareas lying mutually adjacent in the Y-axis direction have differentcolors from each other, the control means preferably controls the liquiddroplet ejection apparatus such that function liquid droplets areejected in the two pixel areas through mutually different main scanningoperations.

According to the above arrangement, function liquid droplets ofdifferent colors are not ejected and landed in respective pixel areaslying mutually adjacent in the Y-axis direction through a common mainscanning operation, thereby reliably preventing function liquid dropletsof different colors from mixing with each other between the pixel areaslying mutually adjacent not only in the X-axis direction but also in theY-axis direction.

In these cases, a drive source of the Y-axis table preferably includes alinear motor.

According to the above arrangement, the plurality of carriage units canbe independently and also accurately moved.

In these cases, each of the carriage units preferably has a plurality ofcolor-dependent function liquid tanks placed thereon, for feedingfunction liquid of a plurality of colors to each of the plurality ofcolor-dependent function liquid droplet ejection heads.

According to the above arrangement, the length between the functionliquid tank and the corresponding function liquid droplet ejection headcan be reduced, and also, the layout of function liquid tubes betweenthe function liquid tanks and the corresponding function liquid dropletejection heads can be simplified. Thus, the function liquid dropletejection heads can stably eject function liquid droplets.

A pressure regulator is preferably interposed between the functionliquid tank and the function liquid droplet ejection head. With thisstructure, since a head pressure between the function liquid tank andthe function liquid droplet ejection head does not excessivelyfluctuate, the function liquid droplet ejection head stably ejectsfunction liquid droplets.

It is preferable that the liquid droplet ejection apparatus furtherinclude a flushing unit disposed on the X-axis table and flushing eachof the ejection nozzles of the function liquid droplet ejection headupon a main scanning operation and that the flushing unit be formed soas to correspond to a head-ejection covering-range over which iscovered, with respect to the Y-axis direction, by all of the functionliquid droplet ejection heads of the plurality of carriage units in asub-scanning operation.

According to the above arrangement, even when the carriage units aresubjected to a sub-scanning operation and move in the Y-axis directionwithin the head-ejection covering-range, the flushing unit can receivefunction liquid droplets flushed from all function liquid dropletejection heads placed on the plurality of carriage units, therebypreventing function liquid droplets from flying off in the vicinity ofeach function liquid droplet ejection head and also maintaining allfunction liquid droplet ejection heads in a satisfactory condition. Whensub-scanning operations are performed n-times for performing an imagingprocess, the head-ejection covering-range is equivalent to the length ofthe imaging line extended in the Y-axis direction by n-times of thepartial imaging line. The flushing unit is preferably formed in theX-axis direction so as to correspond to the length of the plurality ofcarriage units extending in the X-axis direction.

In this case, as described above, when the plurality of color-dependentfunction liquid droplet ejection heads of each carriage unit arearranged such that the plurality of color-dependent partial imaginglines are repeatedly connected one another in the Y-axis direction in apredetermined order so as to make up a single divided imaging line, eachpartial imaging line has a shorter length, thereby leading to a shorterhead-ejection covering-range. Accordingly, the flushing unit has ashorter length in the Y-axis direction, thus contributing to reducingthe space of the function liquid droplet ejection apparatus.

It is preferable that a maintenance area be formed on a movingtrajectory of the carriage units moved by the Y-axis table so as to lieoutside one of the sides of the X-axis table; that the liquid dropletejection apparatus further includes maintenance means provided in themaintenance area; and that the control means controls the liquid dropletejection apparatus such that at least one function liquid dropletejection head not driven during an arbitrary single main scanningoperation faces the maintenance means before the following main scanningoperation so as to be subjected to a function-recovery process.

According to the above arrangement, even when function liquid ofejection nozzles of non-driven function liquid droplet ejection heads isdried during a main scanning operation, the ejection nozzles areprevented from clogging by applying a function-recovery process to thesefunction liquid droplet ejection heads.

An arbitrary single main scanning operation is defined such that, forexample, function liquid droplets are ejected and landed in pixel areaslying at the end of a substrate in the Y-axis direction not by functionliquid droplet ejection heads placed on the outermost end of thecorresponding carriage unit in the Y-axis direction, but by functionliquid droplet ejection heads of other colors placed inside theforegoing ones. In this case, because of facing the substrate outside inthe Y-axis direction, function liquid droplet ejection heads lyingoutside, with respect to the Y-axis direction, the function liquiddroplet ejection heads of other colors driven for ejecting functionliquid droplets in the pixel areas lying at the end of the substrate inthe Y-axis direction are not driven for ejecting function liquiddroplets in this main scanning operation. Accordingly, thefunction-recovery process may be applied to these function liquiddroplet ejection heads before the following main scanning operation asperformed in the structure of the liquid droplet ejection apparatus.

It is preferable that a pair of maintenance areas be provided on amoving trajectory of the carriage units moved by the Y-axis table so asto lie outside both sides of the X-axis table and that the liquiddroplet ejection apparatus further includes a pair of maintenance meansin the corresponding maintenance areas for applying a function-recoveryprocess to the plurality of ejection nozzles of each function liquiddroplet ejection head.

According to this arrangement, the plurality of carriage units can bemaintained by dividing them into two groups, thereby quickly achieving afunction-recovery process of the function liquid droplet ejection heads.

For example, at the time of replacing the function liquid dropletejection heads with new ones, the carriage units having the functionliquid droplet ejection heads placed thereon, which are needed to bereplaced with new ones, can be arranged so as to face one of the pairmaintenance means for achieving head replacement, and also, the othercarriage units can be arranged so as to face the other maintenance meansfor achieving a function-recovery process, whereby suspending anoperation of the liquid droplet ejection apparatus is not required.

The control means preferably controls the liquid droplet ejectionapparatus such that the function liquid droplet ejection heads notdriven during an arbitrary single main scanning operation are arrangedso as to face the maintenance means for achieving a function-recoveryprocess before the following main scanning operation.

According to another aspect of this invention, there is provided amethod of manufacturing an electrooptical device comprising forming afilm-deposited section of function liquid droplets on the substrate byusing the liquid droplet ejection apparatus.

According to still another aspect of this invention, there is providedan electrooptical device comprising a film-deposited section formed onthe substrate with function liquid droplets by using the above-describedliquid droplet ejection apparatus.

According to the above arrangement, the electrooptical device ismanufactured with the liquid droplet ejection apparatus imaging on thework while preventing function liquid droplets of different colors frommixing each other, thereby leading to manufacturing a reliableelectrooptical device. Electrooptical devices (flat panel displays(FPDs)) include a color filter, a liquid-crystal display device, anorganic electro-luminescence (EL) device, a plasma display panel (PDP)device, an electron-emission device, and so forth. The electron-emissiondevices include so-called FED (field emission display) and SED(surface-conduction electron-emitter display).

According to still another aspect of this invention, there is providedan electronic apparatus having incorporated therein the above-describedelectrooptical device.

An electronic apparatus according to this invention includes anelectrooptical device manufactured according to the above-describedmethod.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan of a work (substrate);

FIGS. 2A through 2C illustrate an example color arrangement pattern of acolor filter, composed of three colors R, G, and B;

FIG. 3 is a schematic plan view of an imaging system;

FIG. 4 is an external perspective view of a liquid droplet ejectionapparatus according to a first embodiment of this invention;

FIG. 5 is a plan view thereof;

FIG. 6 is an elevational view thereof;

FIG. 7 is a side view thereof;

FIG. 8 illustrates a plurality of carriage units, each including a headplate having other components placed thereon;

FIGS. 9A and 9B illustrate the carriage unit, wherein FIG. 9A is anexternal perspective view of the carriage unit, and FIG. 9B shows thecarriage unit viewed from below;

FIG. 10 illustrates sub-scanning operations for performing an imagingprocess, in which the seven carriage units move in the Y-axis directionrelative to a work;

FIG. 11 is an external perspective view of a function liquid dropletejection head;

FIGS. 12A and 12B illustrate function liquid feeding means, wherein FIG.12A illustrates a pressure regulator and other components in thevicinity thereof, and FIG. 12B is a sectional view thereof;

FIG. 13 is an external perspective view of maintenance means;

FIG. 14 is a block diagram illustrating a control system of the liquiddroplet ejection apparatus;

FIGS. 15A and 15B illustrate a first main scanning operation forperforming an imaging process with the liquid droplet ejectionapparatus;

FIGS. 16A and 16B illustrate a second main scanning operation, followingthe first main scanning operation shown in FIGS. 15A and 15B;

FIGS. 17A and 17B illustrate a third main scanning operation followingthe second main scanning operation shown in FIGS. 16A and 16B;

FIGS. 18A and 18B illustrate an imaging process performed by the liquiddroplet ejection apparatus when a color arrangement pattern of the colorfiler, composed of three colors R, G, and B is of a mosaic arrangement;

FIG. 19 is a bottom view of a carriage unit of a liquid droplet ejectionapparatus according to a second embodiment;

FIGS. 20A through 20C illustrate an imaging process performed by theliquid droplet ejection apparatus according to the second embodiment;

FIG. 21 is a flow chart illustrating a process of manufacturing a colorfilter;

FIGS. 22A through 22E are schematic sectional views of the color filter,illustrating it in the order of its manufacturing steps;

FIG. 23 is a sectional view of an essential part of a first example ofliquid crystal device including the color filter according to thisinvention, illustrating the general structure of the first exampleliquid crystal device;

FIG. 24 is a sectional view of the general structure of an essentialpart of a second example of liquid crystal device including the colorfilter according to this invention;

FIG. 25 is a sectional view of the general structure of an essentialpart of a third example of liquid crystal device including the colorfilter according to this invention;

FIG. 26 is a sectional view of an essential part of a display deviceserving as an organic EL device;

FIG. 27 is a flow chart illustrating a manufacturing process of thedisplay device serving as the organic EL device;

FIG. 28 is a sectional view showing the step of forming an inorganicbank layer;

FIG. 29 is a sectional view showing the step of forming an organic banklayer;

FIG. 30 is a sectional view showing the step of forming a holeinjection-transport layer;

FIG. 31 is a sectional view showing the state in which the holeinjection-transport layer is formed;

FIG. 32 is a sectional view showing the step of forming a bluelight-emitting layer;

FIG. 33 is a sectional view showing the state in which the bluelight-emitting layer is formed;

FIG. 34 is a sectional view showing the state in which all colorlight-emitting layers are formed;

FIG. 35 is a sectional view showing the step of forming a cathode;

FIG. 36 is an exploded perspective view of an essential part of adisplay device serving as a plasma display panel (PDP) device;

FIG. 37 is a sectional view of an essential part of a display deviceserving as an electron-emission device (FED device); and

FIGS. 38A and 38B are respectively a plan view of an electron emissionsection and its vicinity of the display device, and a plan view showingthe method of forming the electron-emission section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A liquid droplet ejection apparatus according to a first embodiment ofthis invention will be described with reference to the attacheddrawings. The liquid droplet ejection apparatus according to thisembodiment is installed in an imaging system incorporated in aproduction line of a flat panel display device (FPD) such as aliquid-crystal display device and forms a film-deposited section offunction liquid droplets of three colors R, G, and B on a substrate suchas a color filter by introducing function (or functional) liquid such asspecial ink or luminescent resin liquid into a function liquid dropletejection head. A substrate (work or workpiece) serving as an ejectionobject (imaging object) onto which function liquid droplets are ejectedby the liquid droplet ejection apparatus will be briefly described.

As shown in FIG. 1, a work W is a transparent substrate (glasssubstrate) having dimensions of about 1500 mm long and 1800 mm wide andhas a pair work alignment marks Wm formed respectively at the right andleft peripheries thereof with which its position is recognized by aliquid droplet ejection apparatus 1 (see FIG. 4). The work W has aplurality of pixel areas 507 a defined by a defining-wall section 507 b(a bank-section) and arranged in a matrix pattern, in an area of itssurface having dimensions of 1360 mm long and 1630 mm wide, excludingthe above-mentions peripheries. Each pixel area 507 a is formed as adepression having a square shape in plan view, is enclosed by thedefining-wall section 507 b, and serves as a landing area (see FIG. 22C)of function liquid droplets when a film deposited section, which will bedescribed later, made up by three colors R (red), G (green), and B(blue) (coloring layers 508R, 508G, and 508B) is formed by a functionliquid droplet ejection head 71. According to this embodiment, as shownin FIG. 2A, although a color arrangement pattern composed of theplurality of pixel areas 507 a is of a stripe arrangement in which eachhorizontal row of the matrix of the pixel areas is made up by themutually identical color areas, the pattern may be of a mosaicarrangement in which any three of the three pixel areas 507 a aligningvertically or horizontally in the matrix are made up by three areas ofthree colors R, G, and B (see FIG. 2B). Alternatively, the pattern maybe of a delta arrangement in which the plurality of pixel areas 507 a isaligned in a zigzag pattern (see FIG. 2C).

An imaging system including the liquid droplet ejection apparatus willbe briefly described. FIG. 3 is a diagrammatic plan view of an imagingsystems S. As shown in the figure, the imaging system S is made up bythree sets of imaging units Su and is used for manufacturing a colorfilter by forming the coloring layers 508R, 508G, and 508B of threecolors R, G, and B on a work W (see FIG. 4) introduced in the system.The imaging units Su inherently correspond to the respective colors R,G, and B, and each imaging unit is designed so as to form one of thecoloring layers corresponding one of the colors on a work W (asubstrate) sequentially introduced in the system. Meanwhile, as will bedescribed later, since each liquid droplet ejection apparatus 1installed in the imaging system is constructed so as to eject (imagewith) three kinds function liquid (filter materials) of three colors,each imaging unit Su is capable of forming the coloring layers of threecolors on a work W. That is, the imaging system eliminates a transferoperation of the work W among the imaging units Su, thereby effectivelymanufacturing a color filter.

Each imaging unit Su includes the liquid droplet ejection apparatus 1, awork-carrying in/out device 2 juxtaposed to the liquid droplet ejectionapparatus 1, for carrying a work W in or out from the unit, and a hostcomputer 3 connected to the respective devices, for controlling theoverall imaging units Su, in order to form the three coloring layers508R, 508G, and 508B of three colors. The liquid droplet ejectionapparatus 1 is accommodated in a chamber device 4. The chamber device 4is a so-called thermal chamber having the overall liquid dropletejection apparatus 1 accommodated therein under temperature control soas to eject droplets onto a work W under the condition of a constanttemperature. The chamber device 4 includes a box-shaped chamber mainbody 11 having the overall liquid droplet ejection apparatus 1 directlyaccommodated therein, an air conditioner 12 responsible for temperaturecontrol such that the temperature in the chamber main body 11 isconstant, and a control board (not illustrated) controlling the airconditioner 12. Although not illustrated in the figure, the chamber mainbody 11 has an open/close door formed at the front part of the rightside surface thereof, serving as a work-carrying in/out opening. Forexample, when a work W is introduced into the liquid droplet ejectionapparatus 1, the work W can access to the liquid droplet ejectionapparatus 1 accommodated in the chamber main body 11 through theopen/close door.

The work-carrying in/out device 2 includes a robot arm 13 fortransferring a work W, and, with the robot arm 13, transports anunimaged work W into the imaging unit Su through the open/close door soas to introduce it in the liquid droplet ejection apparatus 1, and alsoretrieves an imaged work W from the liquid droplet ejection apparatus 1for transporting it outside the imaging unit Su.

The host computer 3 is configured by a personal computer and so forthand includes a keyboard 17, a display 18, and so forth other than acomputer main body 16 (see FIG. 14).

An installation space 5 shown in the figure is used for installing adrying device, whereby the drying device for vaporizing afunction-liquid solvent of function liquid ejected on a work W can beinstalled in the imaging unit Su if needed.

The liquid droplet ejection apparatus 1 according to a first embodimentof this invention will be described. As shown in FIGS. 4 to 7, theliquid droplet ejection apparatus 1 includes a large-sized common bed 28installed on the floor; a setting table 41 disposed on the common bed 28and setting a work W (see FIG. 4) thereon; work-moving means 21 (X-axistable) reciprocating the work W in the X-axis direction through thesetting table 41 (that is, scanning it in the main scanning direction);head-moving means 22 (Y-axis table) arranged in a manner of straddlingthe work-moving means 21; a plurality of (seven) carriage units 23, eachhaving a plurality of (twelve) of the function liquid droplet ejectionheads 71 placed thereon (see FIG. 8), movably and independently fixed tothe head-moving means 22; function liquid feeding means 24 composed ofseven function liquid feeding units 101, placed on the seven carriageunits 23, and feeding the respective function liquid droplet ejectionheads 71; maintenance means 25 disposed on the moving trajectory of thecarriage units 23 moved by the head-moving means 22 and lying outside(in the figure, out on the right side of) the work-moving means 21, formaintaining the function liquid droplet ejection heads 71; and aflushing unit 26 disposed on the setting table 41, in charge of functionrecovery of the function liquid droplet ejection heads 71 together withthe maintenance means.

Although not illustrated in the figures, the liquid droplet ejectionapparatus 1 includes liquid feeding/recovering means which feeds liquid(function liquid and cleaning liquid) to each means and retrievesunnecessary liquid from the same; air feeding means feeding compressedair for driving and controlling each means; air sucking means forsucking a work W to the setting table 41 so as to set it on the same; awork-recognizing camera 36 recognizing the position of the work W; ahead-recognizing camera 37 recognizing the positions of the carriageunits 23; a controller 27 (a control section 162, see FIG. 14) connectedto the host computer 3 so as to totally control the overall liquiddroplet ejection apparatus 1, and so forth.

The liquid droplet ejection apparatus 1 has a structure in which, bydriving the function liquid droplet ejection heads 71 in synchronizationwith driving the work-moving means 21, function liquid droplets of threecolors R, G, and B are ejected so as to be landed in the pixel areas 507a formed on a work W for performing an imaging process of the work W,and, at the same time, during non-imaging time, for example, at the timeof replacing a work with a new one, by driving the head-moving means 22,the carriage units 23 face the maintenance means 25, whereby themaintenance means 25 performs a maintenance process of the functionliquid droplet ejection heads 71. As described above, since the liquiddroplet ejection apparatus 1 is accommodated in the chamber device 4,most of processes including these imaging and maintaining processes areperformed in the chamber device 4.

An area formed by moving trajectories of a work W moved by thework-moving means 21 and the carriage units 23 moved by the head-movingmeans 22 serves as an imaging area 31 for performing an imaging processtherein. Also, an area lying on the moving trajectory of the carriageunits 23 moved by the head-moving means 22, and outside the work-movingmeans 21 serves as a maintenance area 32 for a maintenance process,which will be performed by the maintenance means 25. The maintenancearea 32 also serves as a head-replacement area for replacing thefunction liquid droplet ejection head 71 with new one. Meanwhile, theother end (lower side in the figure) of the work-moving means 21 servesas a work-carrying in/out area 33 for carrying a work W in or out theliquid droplet ejection apparatus 1, and the work-carrying in/out device2 is disposed so as to face the work-carrying in/out area 33.

The work-moving means 21 is disposed on a stone surface plate 30disposed on the common bed 28 and extending in the X-axis direction. Thework-moving means 21 includes the setting table 41 including anabsorption table 42 setting a work W thereon by absorption and a workθ-table 43 performing fine adjustment of the θ-position of the work W(θ-correction) through the absorption table 42; an X-axis air slider 44slidably supporting the setting table 41 in the X-axis direction; a pairof right and left X-axis linear motors 45 extending in the X-axisdirection and moving the work W in the X-axis direction through thesetting table 41; a pair of X-axis guide rails 46 juxtaposed to theX-axis linear motors 45 and guiding move of the X-axis air slider 44;and an X-axis linear scale (not illustrated) detecting the position ofthe setting table 41. When driven, the pair of X-axis linear motors 45move the X-axis air slider 44 in the X-axis direction while guiding thepair of X-axis guide rails 46 so as to move the work W set on thesetting table 41 in the X-axis direction.

The absorption table 42 has work feeding/removing means 51 incorporatedtherein, for setting an unprocessed work W carried in the work-carryingin/out area 33 on the setting table 41 and for retrieving a processedwork W from the setting table 41. The work feeding/removing means 51includes a lift-up mechanism 56 placing and detaching the work W on andfrom the setting table 41; a pre-alignment mechanism 57 positioning(preliminarily aligning) an unprocessed work W placed on the absorptiontable 42 by the lift-up mechanism 56, relative to the absorption table42, by sandwiching the work W from both the front and rear ends and theright and left ends of the work; and electricity-eliminating means (notillustrated) including an ionizer, for eliminating static electricitycharged on the rear surface of the work W. The flushing unit 26 issupported by the X-axis air slider 44.

While being supported on a pair of front and rear support stands 29extending in the Y-axis direction, the head-moving means 22 bridges theimaging area 31 and the maintenance area 32 and moves each of the sevencarriage units 23 between the imaging area 31 and the maintenance area32. The head-moving means 22 includes seven sets of Y-axis air sliders61 supporting bridge plates 75 at both ends thereof, which will bedescribed later, of the respective seven carriage units 23, so as to bealigned in the Y-axis direction; a pair of Y-axis linear motors 62extending in the Y-axis direction and moving each bridge plate 75 in theY-axis direction, through the corresponding set of the Y-axis airsliders 61; a pair of Y-axis guide rails 63 extending in the Y-axisdirection and guiding move of the seven bridge plates 75; and a Y-axislinear scale (not illustrated) detecting the moving position of eachcarriage unit.

When the pair of Y-axis linear motors 62 is driven, the seven sets ofY-axis air sliders 61 are independently moved, whereby each of the sevencarriage units 23 is individually moved in the Y-axis direction. Hence,this simple structure allows each of the seven carriage units 23 to beaccurately moved independently from each other. As a matter of course,by simultaneously moving the seven sets of Y-axis air sliders 61 in theY-axis direction, the seven carriage units 23 as a united body can bealso moved in the Y-axis direction.

Each of the seven bridge plates 75 supported by the corresponding setsof the Y-axis air sliders 61 has head-use electrical units 66, eachdriving the twelve function liquid droplet ejection heads 71 placed onthe corresponding carriage unit 23; and the function liquid feeding unit101, disposed thereon. The seven head-use electrical units 66 arearranged in a zigzag pattern so as prevent interference with one another(for preventing noise), and the seven function liquid feeding units 101are arranged in a zigzag pattern so as to face the respective head-useelectrical units 66. Also, seven Y-axis cable carriers (not illustrated,Cableveyor: registered trade mark, made by Tsubakimoto Chain Co.)corresponding to the independently movable seven divided carriage units23 and having a tube, a cable, and so forth connected the correspondingcarriage unit 23 accommodated therein so as to follow the move of thecorresponding carriage unit 23 are provided in two groups so as tocorrespond to the seven head-use electrical units 66 in a zigzagarrangement.

When the size of each head-use electrical unit 66 can be reduced, theseven head-use electrical units 66 may be arranged in a line close tothe work-carrying in/out area 33. In this case, the seven functionliquid feeding units 101 can be also arranged in a line close to theside opposite to the work-carrying in/out area 33 instead of zigzagarrangement, thereby easily achieving ink replacement.

As shown in FIG. 6, the respective seven sets of Y-axis air sliders 61of the seven carriage units 23 are supported by the head-moving means 22and aligned in the Y-axis direction. Thus, all nozzles 95 (ejectionnozzles, see FIG. 9B, 12×7 pieces in total) of all function liquiddroplet ejection heads 71 of the seven carriage units make up a singleimaging line L (see FIG. 10). With this structure, by independentlymoving the carriage units 23 from one another to the maintenance area32, every carriage units 23 can be maintained by the maintenance means25, and also, the function liquid droplet ejection heads 71 of everycarriage units 23 can be replaced with new ones, thereby achieving alarge-sized head unit capable of forming a wide imaging line (a longline) without deteriorating workability of maintaining and replacing thefunction liquid droplet ejection heads 71 with new ones.

As long as a single of the imaging line L is formed, the seven carriageunits 23 may be arbitrarily arranged. Also, as a matter of course, thenumber of the carriage units 23 and the number of the function liquiddroplet ejection heads 71 placed on the corresponding carriage unit 23may be arbitrarily set.

As shown in FIGS. 7 to 9, each carriage unit 23 includes the twelvefunction liquid droplet ejection heads 71; a head plate 72 supportingthe twelve function liquid droplet ejection heads 71; twelvehead-holding members 73 fixing the respective twelve function liquiddroplet ejection heads 71 to the head plate 72 from the rear surfacethereof; a carriage 74 supporting the head plate 72; and the bridgeplate 75 having the carriage 74 suspended therefrom and supported by thecorresponding set of the Y-axis air sliders 61 at both ends thereof. Thecarriage 74 includes a head θ-table 76 performing fine adjustment(θ-correction) of the θ-position of the function liquid droplet ejectionheads 71 through the head plate 72.

The head plate 72 is formed of a thick plate composed of a stainlesssteel or the like, having an approximately parallelogram in plan view,positions the twelve function liquid droplet ejection heads 71, and hastwelve fixing perforations (not illustrated) formed therein, for fixingthe respective function liquid droplet ejection heads 71 by thecorresponding head-holding members 73. The head plate 72 also has avalve unit 105 fixed thereon, which will be described later, of thefunction liquid feeding unit 101.

In a state of being placed on the carriage 74, each function liquiddroplet ejection head 71 is positioned and fixed to the head plate 72such that two nozzle rows 94, which will be described later, lieparallel to the Y-axis direction. The twelve function liquid dropletejection heads 71 are arranged in a stepwise pattern in the X-axis andY-axis directions by closely overlapping them one another in their widthdirection and also by shifting them one after another by half the lengthof the nozzle row 94 in their longitudinal direction. Thus, a pluralityof the nozzles 95 lies continuously in the Y-axis direction and forms adivided imaging line LD (see FIG. 10); that is, the above-describedimaging line L is made up by the seven-divided imaging lines LD lyingcontinuously in the Y-axis direction.

In each function liquid droplet ejection head 71, due to the structureof an in-head flow path (not illustrated), which will be describedlater, an ejection amount of each of the nozzles 95 lying at both endsthereof is greater than that of the nozzle 95 lying at the central partthereof; hence, it is preferable that the nozzles 95 lying at both endsthereof be arranged so as to eject no function liquid droplets and theother nozzles 95 serve as ejection nozzles. In this case, the twelvefunction liquid droplet ejection heads 71 are arranged such that thenozzles 95 lying at both ends thereof overlap one another in the Y-axisdirection.

As long as the plurality of the nozzles 95 of each of the twelvefunction liquid droplet ejection heads 71 placed on the head plate 72continuously form the divided imaging line LD in the Y-axis direction,the function liquid droplet ejection heads 71 on the head plate 72 canbe arbitrarily arranged. For example, as will be described in a secondembodiment, the twelve function liquid droplet ejection heads 71 arepossibly divided into two sets, each having six heads, in the Y-axisdirection and also, the function liquid droplet ejection heads 71 ofeach set having six heads are arranged in a stepwise pattern (see FIG.19). As described above, when a plurality of the function liquid dropletejection heads 71 is divided into a plurality of sets and arranged, thehead plate 72 has a reduced width in the X-axis direction. As a matterof course, the number of the function liquid droplet ejection heads 71placed on the corresponding carriage unit 23 can be arbitrarily set.

FIG. 10 illustrates a sub-scanning operation in which, relative to awork W, the seven carriage units 23 move in the Y-axis direction forperforming an imaging process. As shown in the figure, the twelvefunction liquid droplet ejection heads 71 of each carriage unit 23, in aunit of four pieces, serve as R-related function liquid droplet ejectionheads 71R, G-related function liquid droplet ejection heads 71G, andB-related function liquid droplet ejection heads 71B respectively havingthree kinds of function liquid of three colors R, G, and B introducedtherein, in order from the right side of the figure. That is, the twelvefunction liquid droplet ejection heads 71 of each carriage unit 23 arearranged such that partial imaging lines Lp of the respective colors areformed by a plurality of the nozzles 95 of all (four) function liquiddroplet ejection head 71 for each color, and the partial imaging linesLpR, LpG, and LpB of the three colors R, G, and B are connected oneanother in the Y-axis direction, in order from the right side of thefigure, so as to make up a single of the divided imaging line LD. Thus,as the overall seven carriage units 23, the seven partial imaging linesLp for each color are connected one another in the Y-axis direction inorder of R, G, and B colors and make up a single of the imaging line L.

The imaging line L is set so as to have a length equivalent to extendedone of the long side (about 1630 mm) of the area of the surface of thework W, having the pixel areas 507 a formed thereon, extended by twotimes the length (90 mm) the partial imaging line Lp, resulting in about1900 mm, whereby function liquid droplet can be ejected so as to belanded on the entire work W through a common main scanning operation.

In this embodiment, as described above, the color arrangement patterncomposed of the plurality of pixel areas 507 a is formed such that,while any three pixels arranged in the X-axis direction serve as colorpixels of three colors R, G, and B, the plurality of color-dependentfunction liquid droplet ejection heads 71 are arranged so as to beshifted one after another in the Y-axis direction; hence, functionliquid droplet cannot be landed in all pixel areas 507 a through acommon main scanning operation, whereby at least three main scanningoperations must be independently performed. During each time periodamong the three main scanning operations, two sub-scanning operationsare performed so as to move each function liquid droplet ejection head71 by a length of the partial imaging line Lp in the Y-axis directionthrough the corresponding carriage unit 23. These operations will bedescribed in detail later. Accordingly, the seven carriage units 23 movein the Y-axis direction by a length of two times the partial imagingline Lp through three main scanning operations (and two sub-scanningoperations among the three main scanning operations. That is, on theoccasion of performing an imaging process, all function liquid dropletejection head 71 of the seven carriage units 23 cover a range (ahead-ejection covering-range Rh) equivalent to the length of an extendedone of the imaging line L extended by two times (times of the number ofsub-scanning operations) the partial imaging line Lp in the Y-axisdirection.

Although, in FIG. 10, a single of the pixel area 507 a corresponds tothe three function liquid droplet ejection head 71 with respect to theY-axis direction, due to limitation of making the imaging, a pluralityof the pixel areas 507 a practically corresponds to a single of thefunction liquid droplet ejection heads 71.

As shown in FIG. 11, the function liquid droplet ejection head 71 is ofa so-called duplex type and includes a function liquid introductionsection 81 including duplex-type connecting needles 82; a duplex-typehead substrate 83 in connection to the function liquid introductionsection 81; and a head main body 84 connected to the lower part (theupper part in the figure) of the function liquid introduction section 81and having a liquid path formed therein, filled with function liquid.The connecting needles 82 are connected to a function liquid tank 103,which will be described later, and feed function liquid to the liquidpath in the function liquid droplet ejection head 71. The head main body84 includes a cavity 91 composed of a piezoelectric element and soforth; and a nozzle plate 92 having a nozzle surface 93 having the twonozzle rows 94 formed thereon so as to be parallel to each other. Eachnozzle row 94 is made up by a plurality (180 pieces) of the nozzles 95arranged at an equal pitch. The head substrate 83 has duplex-typeconnectors 96 disposed therein, connected to the head-use electricalunit 66 with a flexible flat cable. When the function liquid dropletejection head 71 is driven for ejecting function liquid droplets byapplying a drive waveform on the cavity 91, a pumping action of thecavity 91 causes the nozzles 95 to eject function liquid droplets.

As shown in FIGS. 4 and 5, the function liquid feeding means 24 is madeup by the seven function liquid feeding units 101 corresponding to therespective seven carriage units 23. As shown in FIGS. 8 and 12, eachfunction liquid feeding unit 101 includes a tank unit 102 including aplurality of (twelve) function liquid tanks 103 storing function liquid;twelve function liquid feeding tubes 104 connecting one of the twelvefunction liquid tanks 103 and the corresponding one of the twelvefunction liquid droplet ejection heads 71 to each other; and the valveunit 105 including twelve pressure regulators 106 disposed in therespective twelve function liquid feeding tube 104. A unit of four ofthe twelve function liquid tanks 103 of each tank unit 102 stores acorresponding one of three kinds of function liquid of three colors.Thus, function liquid in each function liquid tank 103 is introduced inthe corresponding function liquid droplet ejection head 71 through thefunction liquid feeding tube 104. For example, the R-related functionliquid droplet ejection head 71R is connected to the function liquidtank 103 storing R-color function liquid and accordingly has R-colorfunction liquid introduced therein.

It is preferable that the function liquid tank 103 be of a resincartridge type having a function liquid pack accommodated therein, inwhich function liquid is packed in a vacuumed state and that functionliquid be previously deaerated.

As shown in FIG. 8, the valve unit 105 is disposed on the head plate 72and includes the twelve pressure regulators 106 and twelve valve-fixingunits 107 fixing the corresponding twelve pressure-regulators 106 to thehead plate 72. The twelve pressure-regulators 106 are disposed on thehead plate 72 so as to be arranged in a stepwise pattern infollowing-suit of the stepwise arrangement of the twelve function liquiddroplet ejection heads 71. By arranging the twelve pressure regulators106 in following-suit of the arrangement of the twelve function liquiddroplet ejection heads 71 as described above, the function liquidfeeding tubes 104 between the function liquid droplet ejection heads 71and the corresponding pressure regulator 106 have the common length,whereby function liquid having the common pressure as one another is fedto the twelve function liquid droplet ejection heads.

While each function liquid tank 103 is placed on the bridge plate 75 inthis embodiment, it may be placed on the head plate 72. This arrangementmakes the length of the function liquid feeding tube 104 extending fromthe function liquid tank 103 to the function liquid droplet ejectionhead 71 shorter, thereby leading to effective use of function liquid.

As shown in FIGS. 12A and 12B, each pressure regulator 106 has astructure in which a valve housing 110 has a first chamber 111 incommunication with the function liquid tank 103; a second chamber 112 incommunication with the function liquid droplet ejection head 71; and acommunication flow-path 113 allowing the first chamber 111 and thesecond chamber 112 to communicate with each other, formed therein. Thesecond chamber 112 has a diaphragm 114 disposed on one of its surfacesso as to face outwards, and a valve disk 115 performing anopening/closing action with the diaphragm 114 is disposed in thecommunication flow-path 113.

Function liquid introduced from the function liquid tank 103 into thefirst chamber 111 is fed to the function liquid droplet ejection head 71through the second chamber 112. On this occasion, the diaphragm 114 isdeformed due to the pressure in the chamber device 4 (generally, theatmospheric pressure). With this deformation, the valve disk 115disposed in the communication flow-path 113 performs an opening/closingaction, and the pressure in the second chamber 112 is adjusted such thatfunction liquid in the second chamber 112 has a slight negativepressure. By disposing the above-described pressure regulator 106between the function liquid tank 103 and the function liquid dropletejection head 71, the head pressure between the function liquid tank 103and the function liquid droplet ejection head 71 does not fluctuateexcessively, thereby allowing function liquid to be stably ejected fromthe function liquid droplet ejection head 71. The valve unit 105 is notlimited to being disposed on the head plate 72 and may be alternatelydisposed on the bridge plate 75.

As shown in FIGS. 5 and 7, the flushing unit 26 is provided forreceiving function liquid droplets ejected by a flushing operation, thatis, ejected by a preliminary (disposal) ejection operation of thefunction liquid droplet ejection head 71, especially for receivingfunction liquid ejected by a regular flushing operation performed, forexample, during replacing a work W with new one. The flushing unit 26lies at the leading side of a work W on the setting table 41, definedwhen the work W moves forward (moves from the lower to upper sides inthe figure), is disposed along the long side of the setting table 41(extending in the Y-axis direction), and includes a regular flushing box121 directly receiving function liquid and a box-supporting member 122fixed to the X-axis air slider 44 and supporting the regular flushingbox 121.

The regular flushing box 121 is formed in a box shape having arectangular shape in plan view and has a member (not illustrated)absorbent to function liquid, disposed at the bottom surface thereof.The long side (extending in the Y-axis direction) of the regularflushing box 121 is formed so as to correspond to the head-ejectioncovering-range Rh. With this arrangement, even when the carriage unit 23performs a sub-scanning operation and then moves in the Y-axis directionin the head-ejection covering-range Rh, the regular flushing box 121 canreceive flushed function liquid ejected from all function liquid dropletejection heads 71 placed on the seven carriage units 23. The short sideof the regular flushing box 121 (extending in the X-axis direction) isalso preferably formed so as to correspond to the length of the sevencarriage units 23 extending in the X-axis direction.

Although not illustrated in the figures, the absorption table 42 has apre-ejection flushing box disposed thereon close to the imaging area 31.When a work W moves forwards in the X-axis direction, the carriage unit23 faces the pre-ejection flushing box and then the work W. Hence, apre-ejection flushing operation can be performed immediately beforefacing the work W, thereby effectively preventing the nozzles fromclogging. The long side of the pre-ejection flushing box (extending inthe Y-axis direction) is formed so as to correspond to the head-ejectioncovering-range Rh in the same fashion as the regular flushing box 121.

Although, in this embodiment, function liquid droplets are ejected andlanded onto a work W only when the work W moves forwards, functionliquid droplets may be ejected from the function liquid droplet ejectionhead 71 also when a work W moves backwards (from the upper to lowersides in FIG. 5). In this case, a pair of the pre-ejection flushingboxes is preferably provided so as to sandwich the setting table 41 inthe X-axis direction. With this structure, a flushing operation can beperformed immediately before drive for ejecting function liquid dropletsin accordance with reciprocal move of a work W.

As described above, the flushing operations is made up by thepre-ejection flushing operation performed immediately before ejectingfunction liquid droplets onto (imaging on) a work W and the regularflushing operation performed when an imaging operation performed onto awork W is temporarily suspended, for example, at the time of replacingthe work W with new one.

Referring now to FIG. 13, the maintenance means 25 will be described.The maintenance means 25 includes a suction unit 131, a wiping unit 132,and a unit elevation mechanism 133, which are all disposed in themaintenance area 32 (see FIGS. 5 and 6).

The suction unit 131 serves for sucking the function liquid dropletejection heads 71 so as to forcefully expel function liquid from thesame. The suction unit 131 is made up by seven divided suction units 141so as to correspond to the seven carriage units 23. The seven dividedsuction units 141 are arranged in the Y-axis direction in following-suitof the arrangement of the seven carriage units 23 and are alsoindividually supported by the unit elevation mechanism 133 so as to beelevatable.

Each divided suction unit 141 faces the corresponding carriage unit 23from the lower side thereof and includes a cap unit 142 including twelvecaps 143 sealing the corresponding nozzle surfaces 93 of the twelvefunction liquid droplet ejection heads 71; a cap-supporting member 145supporting the cap unit 142 so as to be elevatable; and an ejector (notillustrated) applying a suction force on the function liquid dropletejection heads 71 through the respective sealing caps 143.

The cap unit 142 has a structure in which a cap base 144 having thetwelve caps 143 disposed thereon so as to correspond to the arrangementof the twelve function liquid droplet ejection heads 71 placed on thecorresponding the carriage unit 23. With this structure, as the overallsuction unit 131, the caps 143 having a number of twelve multiplied byseven (12×7 pieces) are arranged in following-suit of the arrangementpattern of all function liquid droplet ejection heads 71 placed on theseven carriage units 23, whereby the caps 143 corresponding to allfunction liquid droplet ejection heads 71 can be use for sealing thesame at once. By driving the ejector in a state in which the nozzlesurfaces 93 are sealed by the respective caps 143, function liquid issucked from the nozzles 95. With this operation, function liquid havingan increased viscosity in the function liquid droplet ejection head 71can be removed. As will be described later, since the nozzle surfaces 93of some of the function liquid droplet ejection heads 71 sucked by thesuction unit 131 sometimes have function liquid droplets accretedthereon, the function liquid droplet ejection heads 71 are arranged soas to face the wiping unit 132 for undergoing a wiping operation.

The suction unit 131 is provided not only for sucking the functionliquid droplet ejection heads 71 but also for receiving function liquidexpelled by the regular flushing operation as described above. In otherwords, each cap 143 of the suction unit 131 serves also as the flushingbox. The suction unit 131 can be also used for preventing the nozzles 95from drying by sealing the nozzle surfaces 93 of the function liquiddroplet ejection heads 71 by the corresponding caps 143, for example,during a non-imaging process of the liquid droplet ejection apparatus 1.

The wiping unit 132 is disposed between the imaging area 31 and thesuction unit 131, that is, close to the imaging area 31 in themaintenance area 32, and, with a wiping sheet 151, wipes dirty nozzlesurfaces having function liquid droplets accreted thereon, for example,by sucking the function liquid droplet ejection heads 71. With such anarrangement, the wiping unit 132 can successively face the carriageunits 23 sucked by the suction unit 131 and moving individually to theimaging area 3, thereby allowing the function liquid droplet ejectionheads 71 to be subjected to a wiping process.

Also, the wiping unit 132 includes a delivery reel 152 (an upper one inthe figure) delivering out the wiping sheet 151 (in its extendingdirection); a take-up reel 153 (lower one in the figure) taking up thedelivered wiping sheet 151; a cleaning-liquid feeding unit (notillustrated) dispersing cleaning liquid across the delivered wipingsheet 151; a wipe-out unit 154 facing the function liquid dropletejection heads 71 from the lower side thereof and wiping out the nozzlesurfaces 93 with the wiping sheet 151; and a wiping frame 155 supportingthese components. Cleaning-liquid fed to the wiping sheet 151 is asolvent of relatively volatile function liquid, thereby effectivelyeliminating functional drupelets accreted on the nozzle surfaces 93 ofthe function liquid droplet ejection heads 71.

By driving the head-moving means 22 so as to cause the carriage units 23to successively face the wiping unit 132 one by one, by bringing thewiping sheet 151 having cleaning liquid contained therein in a state ofcontacting with the nozzle surfaces 93 of the twelve function liquiddroplet ejection heads 71, and also by moving the carriage unit 23 inthe Y-axis direction (toward the imaging area 31) with the head-movingmeans 22, the nozzle surfaces 93 are wiped out by the wiping sheet 151.With this arrangement, the twelve function liquid droplet ejection heads71 placed on the corresponding carriage unit 23 are successively wiped.Since a wiping operation is performed in a direction in agreement withthat of the nozzle rows 94 (in the Y-axis direction), mutually differentkinds of function liquid are not wiped by the common part of the wipingsheet 151, thereby preventing the different kinds of function liquidfrom mixing with each other on the nozzle surfaces. 93.

The unit elevation mechanism 133 includes eight divided unit elevationmechanisms 156 individually supporting the seven divided suction units141 of the suction unit 131 and the wiping unit 132 so as to beelevatable. Each divided unit elevation mechanism 156 is made up by acylinder and so forth and individually elevates the seven dividedsuction units 141 and the wiping unit 132 between a predeterminedmaintenance position (an access position) for maintaining the functionliquid droplet ejection head 71 and a predetermined retraction positionof the same. During replacing the function liquid droplet ejection head71 with new one, by driving each divided unit elevation mechanism 156 soas to move down the suction unit 131 and the wiping unit 132, a workingarea is kept above the suction unit 131 and the wiping unit 132.

As described above, since the function liquid droplet ejection head 71undergoes a sucking operation by the suction unit 131 and a wipingoperation by the wiping unit 132, the ejecting feature of the functionliquid droplet ejection heads 71 of each carriage unit 23 can besatisfactorily maintained. In addition, the suction unit 131 is made upby the seven divided suction units 141 so as to correspond to the sevencarriage units 23, thereby achieving easy assembling work of eachdivided suction unit 141.

While the maintenance means is provided in a single of the maintenancearea 32 in this embodiment, as shown in FIGS. 5 and 6, a pair of themaintenance areas 32 may be provided on the moving trajectory of thecarriage units 23 moved by the head-moving means 22 and outside bothsides of the work-moving means 21 (the imaging area 31) such that themaintenance areas 32 have the respective maintenance means 25 disposedtherein. With this structure, the seven carriage units 23 can bemaintained by dividing them into two groups (for example, one group ofthree pieces and the other group of four pieces), a function-recoveryprocess of the function liquid droplet ejection heads 71 can be quicklyperformed. Also, for example, during replacing the function liquiddroplet ejection head 71 with new one, one group of the carriage units23 can be arranged so as to face one of the pair of the maintenancemeans 25 for achieving head replacement, and, at the same time, theother group of the carriage units 23 can be arranged so as to face theother maintenance means 25 for achieving the function-recovery processof the function liquid droplet ejection heads 71 of these carriage units23, thereby leading to no requirement of suspending an operation of theliquid droplet ejection apparatus 1. In the case of providing the pairof maintenance areas 32 as described above, the number of the dividedsuction units 141 making up the suction unit 131 of each maintenancemeans can be three or four.

Referring now to FIG. 14, the control system of the overall liquiddroplet ejection apparatus 1 will be described. The control system ofthe liquid droplet ejection apparatus 1 basically includes the foregoinghost computer 3; the function liquid droplet ejection heads 71, a drivesection 161 including a variety of drivers and driving the work-movingmeans 21, the head-moving means 22, the maintenance means 25, and soforth; and the control section 162 (the controller 27) totallycontrolling the overall liquid droplet ejection apparatus 1 includingthe drive section 161.

The drive section 161 includes a move-use driver 171 individuallycontrolling drive of a motor of each of the work-moving means 21 and thehead-moving means 22; a head driver 172 controlling drive of thefunction liquid droplet ejection heads 71 for ejecting function liquid;a maintenance-use driver 173 controlling drive of each of the suctionunit 131 of the maintenance means 25, the wiping unit 132, and the unitelevation mechanism 133.

The control section 162 includes a CPU 181; a ROM 182; a RAM 183; and aP-CON 184, and these components are connected to one another with a bus185. The ROM 182 has a control program area storing, for example, acontrol program processed by the CPU 181 and a control data area storingcontrol data for performing an imaging operation, a function-recoveryprocess, and the like.

The RAM 183 has a variety of storing sections such as an imaging-datastoring section storing imaging data for imaging on a work W and apositional-data storing section storing positional data of the work andthe function liquid droplet ejection heads 71, other than a variety ofregister groups. Also, the RAM 183 serves as a working area forprocessing the controls. The P-CON 184 has the work-recognizing camera36, the head-recognizing camera 37, and the like, connected thereto, inaddition to the variety of drivers of the drive section 161. Also, theRAM 183 has a logical circuit incorporated therein, for compensating thefunction of the CPU 181 and processing an interface signal with aperipheral circuit. Hence, the P-CON 184 takes a variety of commands orthe like from the host computer 3 in the bus 185 directly or afterprocessing them and, in conjunction with the CPU 181, outputs data or acontrol signal, outputted from the CPU 181 and the like to the bus 185,to the drive section 161 directly or after processing them.

The CPU 181 receives a variety of detection signals, a variety ofcommands, a variety of data and so forth through the P-CON 184 inaccordance with the control program stored in the ROM 182, processes avariety of data and the like stored in the RAM 183, and then outputs avariety of signals to the drive section 161 and so forth through theP-CON 184, thus controlling the overall liquid droplet ejectionapparatus 1. For example, the CPU 181 controls the function liquiddroplet ejection heads 71, the work-moving means 21, and the head-movingmeans 22 so as to image (or draw) on a work W under predeterminedimaging and moving conditions.

A series of imaging process performed by the liquid droplet ejectionapparatus 1 will be described. An unprocessed work W lying in thework-carrying in/out area 33 is first introduced on the setting table 41by the work-carrying in/out device 2. On the almost same occasion, theseven carriage units 23 are moved to the imaging area 31 (a homeposition) by driving the head-moving means 22. Subsequently, as apreliminary preparation for ejecting function liquid droplets, theposition of the work W set on the absorption table 42 is corrected inthe X-axis and θ-axis directions by the work-moving means 21 and thework θ-table 43, respectively, and also, the position of each carriageunit 23 is corrected in the Y-axis and the θ-axis directions by thehead-moving means 22 and by the head θ-table 76, respectively.Correction of the positions brings about a state in which the pluralityof pixel areas 507 a formed on the work W is arranged in the X-axis andY-axis directions so as to form a matrix pattern.

As shown in FIGS. 15A and 15B, since the color arrangement pattern is ofstripe arrangement according to this embodiment, pixel rows ofrespective colors are formed in the Y-axis direction. In other words,adjacent three pixels are arranged so as to serve as three color pixelsof R, G, and B colors in the X-axis direction. When the seven carriageunits 23 lie at the home position as described above, the right-endB-related function liquid droplet ejection heads 71B of the carriageunit 23 shown at the right end in the figure face the pixel areas 507 ashown at the right end in the figure, and the R-related and G-relatedfunction liquid droplet ejection heads 71R and 71G lying outside (out onthe right side of) the above-described ejection heads 71B in the Y-axisdirection lie outside the pixel areas 507 a in the Y-axis direction. Onthis occasion, the left-end B-related function liquid droplet ejectionheads 71B of the carriage unit 23 shown at the left end in the figureface the pixel areas 507 a at the left end in the figure (see FIG. 15A).

In this state, under control of the controller 27 (the control section162), the plurality of pixel areas 507 a is subjected to a main scanningoperation by the liquid droplet ejection apparatus 1 in synchronizationwith forward-move of the work W in the X-axis direction moved by thework-moving means 21, for achieving simultaneously ejecting and landingof function liquid droplets of three colors R, G, and B on the basis ofthe stripe alignment color pattern. Meanwhile, while the pixel areas 507a of the three colors of R, G, and B are alternately arranged in theX-axis direction, a plurality of the color-dependent partial imaginglines Lp lies continuously in the Y-axis direction, whereby functionliquid droplets of mutually different colors are not ejected in thepixel areas 507 a, lying mutually adjacent in the X-axis direction,through a common main scanning operation. In other words, each functionliquid droplet ejection head 71 ejects a function liquid droplet only ina single of the three pixel areas 507 a lying in the X-axis direction(see FIG. 15B).

Upon finishing a first main scanning operation (forward move of the workW), the work W is moved backwards by the work-moving means 21, and also,by driving the head-moving means 22, the seven carriage units 23 as aunited body are moved in the Y-axis direction (leftwards in the figure)by the length of the partial imaging line Lp (equivalent to fourfunction liquid droplet ejection heads) for performing a sub-scanning.As shown in FIGS. 16A and 16B, through this sub-scanning operation, theG-related function liquid droplet ejection heads 71G face the pixelareas 507 a in which B-color function liquid is landed through the firstmain scanning operation; the B-related function liquid droplet ejectionheads 71B face the pixel areas 507 a in which R-color function liquid islanded through the same operation; and the R-related function liquiddroplet ejection heads 71R face the pixel areas 507 in which G-colorfunction liquid is landed through the same operation. While theG-related function liquid droplet ejection heads 71G lying outside (outon the right side of) the pixel areas 507 a in the Y-axis directionthrough the first main scanning operation face the pixel areas 507 alying at the right end in the figure, the R-related function liquiddroplet ejection heads 71R still lie outside the pixel areas 507 a inthe Y-axis direction. Also, the left end B-related function liquiddroplet ejection heads 71B of the carriage unit 23 shown at the left endin the figure facing the pixel areas 507 a shown at the left end in thefigure during the first main scanning operation lie outside (out on theleft side of) the pixel areas 507 a in the Y-axis direction, and theG-related function liquid droplet ejection heads 71G adjacent to theB-related heads 71B on the right face the pixel areas 507 a shown at theleft end in the figure (see FIG. 16A).

In this state, in the same fashion as the first main scanning operation,a second main scanning operation is performed (see FIG. 16B). Althoughthe G-related function liquid droplet ejection heads 71G lying outsidethe pixel areas 507 a (close to the maintenance area 32) in the Y-axisdirection during the first main scanning operation eject no functionliquid droplets in the pixel areas 507 a during this operation, apre-ejection flushing operation is applied to the pre-ejection flushingbox immediately before facing the work W during the first and secondmain scanning operations, thereby appropriately ejecting function liquiddroplets in the pixel areas 507 a during the second main scanningoperation without a drying problem of the nozzles 95.

During a time period between the first and second main scanningoperations, a maintenance process may be performed by the suction unit131 and the wiping unit 132 by moving only the carriage unit 23 shown atthe right end in the figure to the maintenance area 32. With thisarrangement, even when the nozzles 95 of, for example, the R-relatedfunction liquid droplet ejection heads 71R and the G-related functionliquid droplet ejection heads 71G performing no ejection drive duringthe first main scanning operation are dried to an extent in which theirfunction recovery cannot be fully achieved only by applying apre-ejection flushing operation thereto immediately before the secondmain scanning operation, their ejecting functions can be appropriatelyrecovered. During a maintenance process of the function liquid dropletejection heads 71 of the right-end carriage unit 23, the function liquiddroplet ejection heads 71 of the other carriage units 23 lie preferablyon standby while the regular flushing box 121 performs a flushing actionif needed. Also, even when the function liquid droplet ejection heads 71performing no ejection drive lie out the right-end carriage unit 23because of their ejection pattern, a maintenance process may beperformed with the suction unit 131 and the wiping unit 132 by movingthe carriage unit 23 having the function liquid droplet ejection heads71 placed thereon (and the other carriage units 23 closer to themaintenance area 32 than the above-described ones) to the maintenancearea 32.

Upon finishing the second main scanning operation, a sub-scanningoperation in which the work W is moved backwards in the X-axis directionby the work-moving means 21, and, at the same time, by driving thehead-moving means 22, the seven carriage units 23 as a united body aremoved in the Y-axis direction (leftwards in the figure) by a length ofthe partial imaging line Lp (equivalent to the four function liquiddroplet ejection heads). As shown in FIGS. 17A and 17B, with thissub-scanning operation, the R-related function liquid droplet ejectionheads 71R face the pixel areas 507 a in which G-color function liquid islanded through the second main scanning operation; the G-relatedfunction liquid droplet ejection heads 71G face the pixel areas 507 a inwhich B-color function liquid is landed through the same operation; andthe B-related function liquid droplet ejection heads 71B face the pixelareas 507 a in which R-color function liquid is landed through the sameoperation. The R-related function liquid droplet ejection heads 71Rlying outside (out on the right side of) the pixel areas 507 a in theY-axis direction during the second main scanning operation face thepixel areas 507 a shown at the right end in the figure. Also, the leftend G-related function liquid droplet ejection heads 71G of the carriageunit 23 shown at the left end in the figure, facing the pixel areas 507a shown at the left end in the figure during the second main scanningoperation, lie outside (out on the left side of) the pixel areas 507 ain the Y-axis direction, and the R-related function liquid dropletejection heads 71R adjacent to the G-related heads 71G on the right facethe pixel areas 507 a shown at the right end in the figure (see FIG.17A).

In this state, in the same fashion as the second main scanning operationa third main scanning operation is performed (see FIG. 17B). Althoughthe R-related function liquid droplet ejection heads 71R lying outsidethe pixel areas 507 a in the Y-axis direction (towards the maintenancearea 32) during the second main scanning operation eject no functionliquid droplets in the pixel areas 507 a during the common period,pre-ejection flushing operations are applied to the pre-ejectionflushing box immediately before facing the work W during the first tothird main scanning operations, thereby appropriately ejecting functionliquid droplets in the pixel areas 507 a during the third main scanningoperation without a drying problem of the nozzles 95.

Also, in this case, by moving only the carriage unit 23 shown at theright end in the figure to the maintenance area 32, a maintenanceprocess may be performed by the suction unit 131 and the wiping unit 132between the second and third main scanning operations. In addition, asdescribed above, when a pair of the maintenance areas 32 is providedoutside both sides of the imaging area 31, by moving only the carriageunit 23 lying shown at the left end in the figure to the maintenancearea 32 lying on the left side in the figure, a maintenance process maybe performed.

As described above, ejection and landing of function liquid droplets inall pixel areas 507 a formed on the work W are finished without ejectingand landing the function liquid droplets of mutually different colorsbetween the pixel areas 507 a lying mutually adjacent in the X-axisdirection through a common main scanning operation. Hence, even when,for example, R-color function liquid droplets are landed on a part ofthe defining-wall section 507 b lying between the pixel areas 507 alying mutually adjacent in the X-axis direction through the first mainscanning operation and also even when G-color function liquid dropletsare landed on the same through the second main scanning operation, theR-color function liquid droplets landed through the first main scanningoperation are dried to a certain extent at the time of landing of theG-color function liquid droplets through the second main scanningoperation, whereby both kinds of function liquid are prevented frommixing with each other. As a result, function liquid droplets ofmutually different colors are reliably prevented from mixing with eachother between the pixel areas 507 a lying mutually adjacent in theX-axis direction.

Function liquid droplets may be ejected and landed in each pixel area507 a plural times through a common main scanning operation byreciprocating the work W plural times. In this case, each carriage unit23 is preferably moved slightly in the Y-axis direction everyreciprocating moves. With this arrangement, function liquid droplets canbe ejected and landed in across the entire area of each pixel area 507a. Although, in FIGS. 15 to 17, a single of the pixel area 507 acorresponds to three of the function liquid droplet ejection heads 71with respect to the Y-axis direction, due to limitation of making theimaging, a plurality of the pixel areas 507 a practically corresponds toa single of the function liquid droplet ejection heads 71 as describedabove.

In this embodiment, as described above, since the color arrangementpattern composed of the pixels is of a stripe arrangement and a row ofeach pixels of each color is formed in the Y-axis direction, functionliquid droplets of mutually different colors are not landed in each ofthe pixel areas 507 a lying mutually adjacent in the Y-axis direction.In the case where the color arrangement pattern composed of the pixelsis of a mosaic arrangement or a delta arrangement, since pixels ofdifferent colors area are arranged in the Y-axis direction, whenfunction liquid droplets are landed in two of the pixel areas 507 alying mutually adjacent in the Y-axis direction and corresponding to thefunction liquid droplet ejection heads 71 of different colors lyingmutually adjacent in the Y-axis direction through a common main scanningoperation, there is a risk that two kinds of function liquid droplets ofdifferent colors are respectively landed on a part of the defining-wallsection 507 b lying between the adjacent pixel areas and are mixed witheach other on the above-described part. In such a case, function liquiddroplets of different colors are preferably ejected in the two pixelareas 507 a through mutually different main scanning operations. Such anoperation is especially effective when a large amount of function liquiddroplets are ejected in the pixel areas 507.

As shown in FIGS. 18A and 18B, when the color arrangement pattern of thepixels is of a mosaic arrangement, for example, with respect to two ofthe pixel areas 507 a lying mutually adjacent in the Y-axis directionrespectively corresponding to the R-related and G-related functionliquid droplet ejection heads 71R and 71G mutually adjacent in theY-axis direction, through the first main scanning operation, theG-related function liquid droplet ejection heads 71G (a part of thenozzles 95 of the ejection heads 71G) is not driven, and the R-relatedfunction liquid droplet ejection heads 71R are driven for ejectingR-color function liquid droplets (see FIG. 18A). Through the second mainscanning operation, the R-related function liquid droplet ejection heads71R are not driven, and the G-related function liquid droplet ejectionheads 71B are driven for ejecting G-color function liquid droplets (seeFIG. 18B). With this arrangement, through a common main scanningoperation, function liquid droplets of mutually different colors are notlanded between the pixel areas 507 a lying mutually adjacent in theY-axis direction. As a result, function liquid droplets of mutuallydifferent colors are reliably prevented from mixing with each otherbetween the pixel areas 507 a lying mutually adjacent not only in theX-axis direction but also in the Y-axis direction.

Although, in FIGS. 18A and 18B, due to limitation of making the imaging,a single of the pixel area 507 a corresponds to a single of the functionliquid droplet ejection heads 71 in the Y-axis direction, as describedabove, a single of the function liquid droplet ejection heads 71practically corresponds to a plurality of the pixel areas 507 a.

Referring now to FIGS. 19 and 20, a liquid droplet ejection apparatusaccording to the second embodiment will be described. Although a liquiddroplet ejection apparatus 1 according to the second embodiment hassubstantially the same structure as that of the liquid droplet ejectionapparatus 1 according to the first embodiment. There is a differencebetween them. That is, in the first embodiment, the twelve functionliquid droplet ejection heads 71 of each carriage units 23 are arrangedin a single stepwise row, and, in a unit of four pieces, serve as theR-related function liquid droplet ejection heads 71R, the G-relatedfunction liquid droplet ejection heads 71G, and the B-related functionliquid droplet ejection heads 71B having respective three kinds offunction liquid of three colors introduced therein (see FIGS. 9 and 10).Whereas, in the second embodiment, the twelve function liquid dropletejection heads 71 are divided into two sets six heads each in the Y-axisdirection, and, at the same time, the six function liquid dropletejection heads 71 of each set are arranged in a stepwise pattern so asto serve as the R-related function liquid droplet ejection head 71R, theG-related function liquid droplet ejection head 71G, and the B-relatedfunction liquid droplet ejection head 71B having the respective threekinds of function liquid of three colors introduced therein, in a unitof a single piece in order from the right side in FIG. 19.

In other words, according to the second embodiment, the twelve functionliquid droplet ejection heads 71 of each carriage units 23 are arrangedsuch that a plurality of the nozzles 95 of the four function liquiddroplet ejection heads 71 of respective colors forms the four partialimaging lines Lp of respective colors, and the partial imaging linesLpR, LpG, and LpB of three colors are repeatedly connected one anotherin the Y-axis direction four times, in order from the right side in thefigure in that order, so as to form a single of the divided imaginglines LD. With this arrangement, each partial imaging line Lp is shorterthan that in the first embodiment.

Referring now to FIGS. 20A through 20C, a series of imaging process ofthe liquid droplet ejection apparatus 1 according to the secondembodiment will be described. In the same fashion as described above, awork is first set on the absorption table 42, and the positions of thework and each of the carriage units 23 are corrected.

On this occasion, the right-end B-related function liquid dropletejection heads 71B of the carriage unit 23 shown at the right end in thefigure face the pixel areas 507 a at the right end in the figure, andthe R-related function liquid droplet ejection heads 71R and theG-related function liquid droplet ejection heads 71G lie outside (on theright of) the above-described pixel areas 507 a in the Y-axis direction.Also, the left end B-related function liquid droplet ejection heads 71Bof the carriage unit 23 shown at the left end in the figure face thepixel areas 507 a at the left end in the figure. In this state, a firstmain scanning operation is performed, and function liquid droplets areejected in only a single of the pixel area 507 a of the three pixelareas 507 a arranged in the X-axis direction by each function liquiddroplet ejection head 71 (see FIG. 20A).

Upon finish of the first main scanning operation, a sub-scanningoperation in which the seven carriage units 23 as a united body aremoved in the Y-axis direction (leftwards in the figure) by a length of apartial imaging line Lp (equivalent to a single function liquid dropletejection head) such that the G-related function liquid droplet ejectionheads 71G face the pixel areas 507 a having B-function liquid landedtherein through the first main scanning operation; the B-relatedfunction liquid droplet ejection heads 71B face the pixel areas 507 ahaving R-function liquid landed therein through the same operation; andthe R-related function liquid droplet ejection heads 71R face the pixels507 a having G-function liquid landed therein through the sameoperation. In other words, with the liquid droplet ejection apparatus 1according to the second embodiment, since each partial imaging line Lpis shorter length than in the first embodiment, each function liquiddroplet ejection head 71 (the carriage unit 23) moves shorter throughthe sub-scanning operation, thereby leading to a shorter time of thesub-scanning operation.

Upon a pre-ejection flushing operation in the same fashion as in thefirst embodiment, a second main scanning operation is performed suchthat G-function liquid is landed in the pixel areas 507 a adjacent tothe pixel areas 507 a having B-function liquid landed therein throughthe first main scanning operation; B-function liquid is landed in thepixel areas 507 a adjacent to the pixel areas 507 a having R-functionliquid landed therein through the same operation; and R-function liquidis landed in the pixel areas 507 a adjacent to the pixel areas 507 ahaving G-function liquid landed therein through the same operation (seeFIG. 20B).

Upon finish of the second main scanning operation, a sub-scanningoperation in which the seven carriage units 23 as a united body aremoved in the Y-axis direction (leftwards in the figure) by a length of apartial imaging line Lp (equivalent to a single function liquid dropletejection head) such that the G-related function liquid droplet ejectionheads 71G face the pixel areas 507 a having B-function liquid landedtherein through the second main scanning operation; the B-relatedfunction liquid droplet ejection heads 71B face the pixel areas 507 ahaving R-function liquid landed therein through the same operation; andthe R-related function liquid droplet ejection heads 71R face the pixels507 a having G-function liquid landed therein through the sameoperation. Likewise, since each partial imaging line Lp is shorter thanin the first embodiment, each function liquid droplet ejection head 71(the carriage unit 23) moves shorter in the sub-scanning operation,thereby leading to a shorter time of the sub-scanning operation.

Upon a pre-ejection flushing operation in the same fashion as describedabove, a third main scanning operation is performed such that G-functionliquid is landed in the pixel areas 507 a adjacent to the pixel areas507 a having B-function liquid landed therein through the second mainscanning operation; B-function liquid is landed in the pixel areas 507 aadjacent to the pixel areas 507 a having R-function liquid landedtherein through the same operation; and R-function liquid is landed inthe pixel areas 507 a adjacent to the pixel areas 507 a havingG-function liquid landed therein through the same operation (see FIG.20C).

As described above, the imaging process according to the secondembodiment is performed in the same fashion as in the first embodiment,excluding a difference in moving distances of the function liquiddroplet ejection heads, and ejection and landing of function liquiddroplets in all pixel areas 507 a formed on the work W are finishedwithout ejecting and landing function liquid droplets of mutuallydifferent colors between the pixel areas 507 a lying mutually adjacentin the X-axis direction through a common main scanning operation.Accordingly, function liquid droplets of different colors are reliablyprevented from mixing with each other between the pixel areas 507 alying mutually adjacent in the X-axis direction.

Also, according to the second embodiment, since each partial imagingline Lp is shorter than in the first embodiment, the head-ejectioncovering-range Rh (equivalent to the length of an extended one of theimaging line L extended by two times (times of the number ofsub-scanning operations) the partial imaging line Lp in the Y-axisdirection) has a shorter length. Accordingly, the pre-ejection flushingbox has a shorter length in the Y-axis direction, thereby leading to areduced space of the liquid droplet ejection apparatus.

Further, also, according to the second embodiment, between the first andsecond main scanning operations and between the second and third mainscanning operations, a maintenance process may be performed by movingonly the carriage unit 23 shown at the right end in the figure to themaintenance area 32. While a wiping operation is performed in adirection in agreement with that of the nozzle rows 94 (extending in theY-axis direction) also in the second embodiment, since function liquidof a common color is introduced in the function liquid droplet ejectionheads 71, arranged at the same position in the X-axis direction, of thecarriage unit 23, (see FIGS. 19 and 20), mutually different kinds offunction liquid are not wiped by a common part of the wiping sheet 151,thereby preventing different kinds of function liquid from mixing witheach other on the nozzle surface. 93.

As descried above, with the liquid droplet ejection apparatus 1according to this embodiment, when function liquid droplets of threecolors R, G, and B are simultaneously ejected and landed on a work W,even when function liquid droplets are not exactly landed in each pixelarea 507 a, function liquid droplets of different colors are preventedfrom mixing with each other.

The structures of a color filter, a liquid-crystal display device, anorganic EL device, a (PDP) device, an electron-emission device such asan FED or SED device, an active matrix substrate incorporated in thesedisplay devices, and the like as examples electrooptical devices (flatpanel displays) manufactured by using the liquid droplet ejectionapparatus 1 according to this embodiment, and methods for manufacturingthese components will be described. The active matrix substrate has thinfilm transistors, and source and data wires electrically connected tothe thin film transistors, formed therein.

A method of manufacturing a color filter incorporated into aliquid-crystal display device, an organic EL device, and the like willbe described. FIG. 21 illustrates a flowchart of a manufacturing processof the color filter, and FIGS. 22A through 22E are schematic sectionalviews of a color filter 500 (a filter substrate 500A) according to thisembodiment, illustrating the process in order of its manufacturingsteps.

In a black-matrix forming step S101, a black-matrix 502 is formed on asubstrate (W) 501 as shown in FIG. 22A. The black-matrix 502 is composedof chromium metal, a laminate of chromium metal and chromic oxide, resinblack, or the like. The black-matrix 502 composed of a thin metal filmis formed by spattering, chemical vapor deposition, or the like. Also,the black-matrix 502 composed of a resin thin film is formed by gravureprinting, photo resist, thermal transfer, or the like.

Subsequently, in a bank-section forming step S102, a bank-section 503 isformed so as to overlie on the black-matrix 502. In other words, asshown in FIG. 22B, a resist layer 504 composed of negative-typetransparent photosensitive resin is formed so as to cover the substrate501 and the black-matrix 502. Then, the uncompleted color filter isexposed in a state in which its upper surface is covered by a mask film505 formed in a matrix pattern.

Further, as shown in FIG. 22C, the resist layer 504 is patterned byetching an unexposed part of the resist layer 504, leading to formingthe bank-section 503. When the black-matrix is composed of resin black,the black-matrix serves also as the bank-section 503.

The bank-section 503 and the black-matrix 502 lying below thebank-section 503 serve as a defining-wall section 507 b defining therespective pixel areas 507 a so as to define landing areas of functionliquid droplets when coloring layers (a deposited-film section) 508R,508G, and 508B are formed by the function liquid droplet ejection heads71 in a coloring-layer forming step which is performed later.

The filter substrate 500A is obtained through the above-describedblack-matrix and bank-section forming steps.

In this embodiment, the bank section 503 is composed of a resin materialwhose coated surface is lyophobic (hydrophobic). Also, the surface ofthe substrate (glass substrate) 501 is lyophilic (hydrophilic), wherebya variance in landing positions of droplets in each of pixel areas 507 aencircled by the bank-section 503 (the defining wall 507 b) isautomatically corrected in a coloring-layer forming step, which will bedescribed later.

Then, as shown in FIG. 22D, in the coloring-layer forming step S103,function liquid droplets are ejected by the function liquid dropletejection heads 71 so as to be landed in respective pixel areas 507 aencircled by the defining wall 507. In this case, with the functionliquid droplet ejection heads 71, function liquid (filter material) ofthree colors (R, G, and B) is introduced and the corresponding functionliquid droplets are ejected. The color arrangement pattern composed ofthree colors R, G, and B can be of a stripe arrangement, a mosaicarrangement, a delta arrangement, or the like.

Subsequently, by fixing the function liquid by drying (for example, byheating), the coloring layers 508R, 508G, and 508B of the three colorsare formed. When the coloring layers 508R, 508G, and 508B are formed,the process moves to a protective-film forming step S104. As shown inFIG. 22E, a protective film 509 is formed so as to cover the uppersurfaces of the substrate 501, the defining wall 507 b, and the coloringlayers 508R, 508G, and 508B.

In other words, after coating liquid for the protective film is ejectedacross the entire surface of the substrate 501 having the coloringlayers 508R, 508G, and 508B formed therein, the liquid is dried and theprotective film 509 is formed.

Then, after the protective film 509 is formed, the color filter 500 ismoved to the following film-depositing step in which a film composed ofITO (indium tin oxide) or the like and serving as transparent electrodesis deposited.

FIG. 23 is a sectional view of an essential part of a passive-matrixliquid crystal device (liquid crystal device) 520 as a first exampleliquid-crystal display device having the foregoing color filter 500incorporated therein, illustrating the general structure of the same.When accessory components such as a liquid-crystal driving IC, abacklight, a support member are placed on the liquid crystal device 520,a transmissive liquid-crystal display device serving as a final productis achieved. Since the color filter 500 is identical to those shown inFIGS. 22A through 22E, the corresponding parts are denoted by the samereference numbers, and the descriptions thereof will be omitted.

The liquid crystal device 520 is generally made up by the color filter500, a counter substrate 521 composed of a glass substrate or the like,and a liquid crystal layer 522 sandwiched by the above two componentsand composed of super twisted nematic (STN) liquid crystal composition,and the color filter 500 lies in the upper part of the figure (close toan observer).

Although not illustrated in the figure, polarizers are disposed on therespective outer surfaces (the respective surfaces opposite to theliquid crystal layer 522) of the counter substrate 521 and the colorfilter 500, and also, a backlight is disposed outside one of thepolarizers lying close to the counter substrate 521.

On the protective film 509 of the color filter 500 (close to the liquidcrystal layer), a plurality of strip-shaped first electrodes 523extending long in the horizontal direction in FIG. 23 is formed at apredetermined interval, and a first alignment film 524 is formed so asto cover the surfaces of the first electrodes 523 opposite to the colorfilter 500.

At the same time, on the surface of the counter substrate 521 opposingthe color filter 500, a plurality of strip-shaped second electrodes 526,each extending long in a direction perpendicular to the first electrodes523 of the color filter 500 is formed at a predetermined interval, and asecond alignment film 527 is formed so as to cover the surfaces of thesecond electrodes 526 close to the liquid crystal layer 522. The firstand second electrodes 523 and 526 are composed of a transparentconductive material such as ITO.

Spacers 528 disposed in the liquid crystal layer 522 maintain thethickness (the cell gap) of the liquid crystal layer 522 constant. Asealant 529 prevents liquid crystal composition in the liquid crystallayer 522 from leaking outside. One end of each of the first electrodes523 extends outside the sealant 529 so as to serve as a routing wire 523a.

Thus, intersections made by the first and second electrodes 523 and 526serve as pixels, and the coloring layers 508R, 508G, and 508B of thecolor filter 500 are arranged so as to lie at the intersections servingas the corresponding pixels.

In the general manufacturing process, the first electrodes 523 arepatterned and the first alignment film 524 is coated on the color filter500 so as to prepare a section including the color filter 500. Inaddition to this, the second electrodes 526 are patterned and the secondalignment film 527 is coated on the counter substrate 521 so as toprepare a section including the counter substrate 521. Then, the spacers528 and the sealant 529 are formed in a section including the countersubstrate 521, and the above-described two sections are bonded to eachother in this state. After liquid crystal constituting the liquidcrystal layer 522 is filled in the liquid crystal layer 522 through aninlet of the sealant 529, the inlet is closed. Subsequently, bothpolarizers and the backlight are deposited.

With the liquid droplet ejection apparatus 1 according to thisembodiment, for example, a spacer material (function liquid) making upthe foregoing cell gap is applied, and, before bonding the sectionincluding the color filter 500 to the section including the countersubstrate 521, liquid crystal (function liquid) can be also uniformlyapplied in the area enclosed by the sealant 529. Also, the foregoingsealant 529 can be printed with the function liquid droplet ejectionheads 71. In addition, both first and second alignment films 524 and 527can be also coated with the function liquid droplet ejection heads 71.

FIG. 24 is a sectional view of the general structure of an essentialpart of a second example liquid crystal device 530 including the colorfilter 500 according to this embodiment.

The liquid crystal device 530 is greatly different from the liquidcrystal device 520 in that the color filter 500 is disposed in the lowerpart of the figure (opposite to an observer).

The liquid crystal device 530 has a general structure in which a liquidcrystal layer 532 composed of STN liquid crystal is sandwiched betweenthe color filter 500 and a counter substrate 531 composed of a glasssubstrate or the like. Although not illustrated in the figure,polarizers and so forth are disposed on the outer surfaces of thecounter substrate 531 and the color filter 500.

On the protective film 509 of the color filter 500 (close to the liquidcrystal layer 532), a plurality of strip-shaped first electrodes 533extending long in a direction perpendicular to the plane of the figureis formed at a predetermined interval, and a first alignment film 534 isformed so as to cover the surfaces of the first electrodes 533 close tothe liquid crystal layer 532.

On the surface of the counter substrate 531 opposing the color filter500, a plurality of strip-shaped second electrodes 536 extendingperpendicular to the first electrodes 533 close to the color filter 500is formed at a predetermined interval, and a second alignment film 537is formed so as to cover the surfaces of the second electrodes 536 closeto the liquid crystal layer 532.

In the liquid crystal layer 532, spacers 538 maintaining the thicknessof the liquid crystal layer 532 constant and a sealant 539 preventing aliquid crystal composition in the liquid crystal layer 532 from leakingoutside are disposed.

In the same fashion as the liquid crystal device 520, intersections madeby the first electrodes 533 and the second electrodes 536 serve aspixels, and the coloring layers 508R, 508G, and 508B of the color filter500 are arranged so as to lie at the intersections serving as thecorresponding pixels.

FIG. 25 is an exploded perspective view of the general structure of atransmissive TFT (thin film transistor) liquid crystal device 550 as athird example liquid crystal device including the color filter 500according to this invention.

The liquid crystal device 550 has a structure in which the color filter500 lies in the upper part of the figure (close to an observer).

The liquid crystal device 550 generally includes the color filter 500; acounter substrate 551 disposed so as to oppose the color filter 500; aliquid crystal layer (not illustrated) sandwiched between above twocomponents; a polarizer 555 disposed on the upper surface of the colorfilter 500 (close to an observer); and a polarizer (not illustrated)disposed on the lower surface of the counter substrate 551.

On the surface of the protective film 509 (close to the countersubstrate 551) of the color filter 500, liquid-crystal drivingelectrodes 556 are formed. The electrodes 556 are composed of atransparent conductive material such as ITO, and serves as a fullsurface electrode covering the entire area where pixel electrodes 560,which will be described later, are formed. Also, an alignment film 557is disposed so as to cover the surfaces of the electrodes 556 oppositeto the pixel electrodes 560.

The counter substrate 551 has an insulating layer 558 on the surfacethereof opposing the color filter 500. The insulating layer 558 hasscanning lines 561 and signal lines 562 formed thereon so as to lieperpendicular to each other. The pixel electrodes 560 are formed inareas encircled by the scanning lines 561 and the signal lines 562.Although an alignment film is formed on the pixel electrodes 560 in anactual liquid crystal device, it is omitted in the figure.

Also, a thin film transistor 563 including a source electrode, a drainelectrode, a semiconductor, and a gate electrode is formed in a sectionencircled by a cut of the pixel electrode 560, each of the scanninglines 561, and each of the signal lines 562. By applying signals on thescanning lines 561 and the signal lines 562, the thin film transistor563 is turned on or off so as to perform current-exciting control of thepixel electrodes 560.

Although each of the foregoing example liquid crystal devices 520, 530,and 550 is of a transmissive type, it can be of a reflective type or atransflective type by providing a reflective layer or a transflectivelayer.

FIG. 26 is a sectional view of an essential part of a display area(hereinafter, simply referred to as a display device 600) of an organicEL device.

The display device 600 has a general structure in which a substrate (W)601 has a circuit-element section 602, a light-emitting element section603, and a cathode 604 deposited thereon.

In the display device 600, light emitted from the light-emitting elementsection 603 toward the substrate 601 passes through the circuit-elementsection 602 and the substrate 601 and is emitted toward an observer,while light emitted from the light-emitting element section 603 towardthe opposite side to the substrate 601 is reflected from the cathode604, then passes through the circuit-element section 602 and thesubstrate 601, and is emitted toward the observer.

The circuit-element section 602 and the substrate 601 have asubstrate-protecting film 606 formed therebetween, composed of a siliconoxide film. The substrate-protecting film 606 has island-shapedsemiconductor films 607 formed thereon (close to the light-emittingelement section 603), composed of polycrystalline silicon. Eachsemiconductor film 607 has a source area 607 a and a drain area 607 brespectively formed in the left and right areas thereof by implantinghighly concentrated cations, and the central part thereof having nocations implanted therein serves as a channel area 607 c.

The circuit-element section 602 has a transparent gate-insulating film608 formed therein, covering the substrate-protecting film 606 and thesemiconductor films 607, in addition to having gate electrodes 609composed of metal such as Al, Mo, Ta, Ti, or W, each formed at aposition on the gate-insulating film 708 so as to correspond to thechannel area 607 c of each semiconductor film 607. The gate electrode609 and the gate-insulating film 608 have transparent first and secondinterlayer insulating films 611 a and 611 b formed thereon. Also, thefirst and second interlayer insulating films 611 a and 611 b havecontact holes 612 a and 762 b perforated therein so as to communicatewith the source area 607 a and the drain area 607 b of the semiconductorfilms 607, respectively.

The second interlayer insulating film 611 b has transparent pixelelectrodes 613 formed thereon in a predetermined pattern, composed ofITO or the like, and each pixel electrode 613 is connected to the sourcearea 607 a through the contact hole 612 a.

The first interlayer insulating film 611 a has a power line 614 disposedthereon and connected to the drain area 607 b through the contact hole612 b.

As described above, the circuit-element section 602 has drivingthin-film transistors 615 formed therein, connected to the respectivepixel electrodes 613.

The light-emitting element section 603 has a general structure in whicheach of a plurality of the pixel electrodes 613 has a function layer 617deposited thereon, and each pixel electrode 613 and the function layer617 have a bank section 618 interposed therebetween so as to define thecorresponding function layer 617.

The pixel electrode 613, the function layer 617, and the cathode 604disposed on the function layer 617 make up a light-emitting element. Thepixel electrodes 613 are patterned in a rectangular shape in plan view,and any two of the pixel electrodes 613 have the bank section 618 formedtherebetween.

The bank section 618 is made up by an inorganic bank layer 618 a (afirst bank layer) composed of an inorganic material such as SiO, SiO₂,or TiO₂ and an organic bank layer 618 b (a second bank layer) (a)deposited on the inorganic bank layer 618 a, (b) composed of, forexample, acrylic resin resist or polyimide resin resist, each havingexcellent thermal resistance and solvent resistance, (c) and having atrapezoidal cross-section. A part of the bank section 618 overlies theperiphery of each pixel electrode 613.

Any mutually adjacent two parts of the bank section 618 have an opening619 therebetween, formed so as to be gradually widened upwards relativeto the pixel electrodes 613.

The function layer 617 is made up by a hole-injecting/transporting layer617 a and a light-emitting layer 617 b formed on thehole-injecting/transporting layer 617 a, both lying above thecorresponding pixel electrode 613 and in the opening 619 in a depositedstate. Another function layer having another function may beadditionally formed so as to lie adjacent to the light-emitting layer617 b. For example, an electron-transporting layer may be formed. Thehole-injecting/transporting layer 617 a transports holes from the pixelelectrode 613 and injects them into the light-emitting layer 617 b. Thehole-injecting/transporting layer 617 a is formed by ejecting a firstcomposition (function liquid) containing a forming material. The formingmaterial can be a known one.

The light-emitting layer 617 b emits light of any one of colors red (R),green (G), and blue (B) and is formed by ejecting a second composition(function liquid) containing a forming material of the light-emittinglayer 617 b (composed of a light-emitting material). Known materialinsoluble to the hole-injecting/transporting layer 617 a is preferablyused as a solvent (a nonpolar solvent) of the second composition. Byusing such a nonpolar solvent in the second composition of thelight-emitting layer 617 b, the light-emitting layer 617 b can be formedwithout causing the hole-injecting/transporting layer 617 a to bedissolved again.

With this structure, since holes injected from thehole-injecting/transporting layer 617 a and electrons injected from thecathode 604 are coupled again in the light-emitting layer 617 b, lightis emitted from this layer.

The cathode 604 is formed so as to cover the entire surface of thelight-emitting element section 603 and serves so as to pass electriccurrent to the function layer 617 together with the pixel electrode 613as a pair. The cathode 604 has a sealing member (not illustrated)disposed thereabove.

Referring now to FIGS. 27 to 35, the manufacturing process of thedisplay device 600 will be described.

As shown in FIG. 27, the display device 600 is manufactured through abank-section forming step S111, a surface-finishing step S112, ahole-injecting/transporting layer forming step S113, a light-emittinglayer forming step S114, and a counter-electrode forming step S115. Themanufacturing process is not limited to that illustrated in the figure,and some steps may be eliminated from or added to the process.

As shown in FIG. 28, in the bank-section forming step S111, theinorganic bank layer 618 a is formed on the second interlayer insulatingfilm 611 b such that an inorganic film is formed at its forming positionand is then patterned by lithography or the like. On this occasion, apart of the inorganic bank layer 618 a overlaps with the periphery ofthe corresponding pixel electrode 613.

When the inorganic bank layer 618 a is formed, as shown in FIG. 29, theorganic bank layer 618 b is formed on the inorganic bank layer 618 a.The organic bank layer 618 b is also formed by way of patterning bylithography or the like in the same fashion as the inorganic bank layer618 a.

The bank section 618 is formed as described above. In accordance withforming the bank section 618, any mutually adjacent two parts of banksection 618 have the opening 619 formed therebetween so as to openupwards relative to the pixel electrodes 613. This opening 619 defines apixel area.

In the surface-finishing step S112, lyophilic and liquid-repellenttreatments are performed. The lyophilic treatment is applied on a firstdeposited section 618 aa of the inorganic bank layer 618 a and anelectrode surface 613 a of the pixel electrode 613, and the surfaces ofthese areas are finished so as to be lyophilic by plasma treatment usingoxygen as a process gas, for example. The plasma treatment serves alsoso as to clean ITO making up the pixel electrodes 613.

Also, the liquid-repellent treatment is applied on wall surfaces 618 sand an upper surface 618 t of the organic bank layer 618 b, and thesesurfaces are finished so as to be liquid-repellent by plasma treatmentusing, e.g., methane tetra-fluoride as a process gas.

By carrying out the surface-finishing step, when the function layer 617is formed with the function liquid droplet ejection head 71, functionliquid droplets can be more reliably landed in the corresponding pixelarea, and also, the function liquid droplets landed in the pixel areaare prevented from leaking from the opening 619.

Thus, a display-device substrate 600A is obtained by carrying out theabove-described steps. The display-device substrate 600A is placed onthe setting table 41 of the liquid droplet ejection apparatus 1 shown inFIG. 1, and the hole-injecting/transporting layer forming step S113 andthe light-emitting layer forming step S114, which will be describedbelow, are carried out.

As shown in FIG. 30, in the hole-injecting/transporting layer formingstep S113, the function liquid droplet ejection head 71 ejects the firstcomposition containing the forming material of thehole-injecting/transporting layer 617 a in the corresponding opening 619making up a pixel area. Then, a polar solvent contained in the firstcomposition is vaporized by drying and heating so as to form thehole-injecting/transporting layer 617 a on the pixel electrode 613 (theelectrode surface 613 a) as shown in FIG. 31.

The light-emitting layer forming step S114 will be described. In thelight-emitting layer forming step S114, as described above, in order toprevent the hole-injecting/transporting layer 617 a from being dissolvedagain, a nonpolar solvent insoluble to the hole-injecting/transportinglayer 767 a is used as a second composition upon forming thelight-emitting layer 617 b.

In the meantime, since the hole-injecting/transporting layer 617 a haslow affinity to a nonpolar solvent, even when the second compositioncontaining a nonpolar solvent is ejected on thehole-injecting/transporting layer 617 a, there is a risk that thehole-injecting/transporting layer 617 a and the light-emitting layer 617b are not closely attached to each other, or the light-emitting layer617 b is not uniformly coated.

In order to improve the affinity of the surface thehole-injecting/transporting layer 617 a to the nonpolar solvent and thelight-emitting layer forming material, a surface finishing treatment (asurface-improving treatment) is preferably carried out prior to formingthe light-emitting layer 617 b. The surface finishing treatment iscarried out by applying a surface-improving material identical orsimilar to the second composition used upon forming the light-emittinglayer 617 b on the hole-injecting/transporting layer 617 a and then bydrying it.

With such treatments, the surface of the hole-injecting/transportinglayer 617 a has affinity to a nonpolar solvent, whereby the secondcomposition containing the light-emitting layer forming material can beuniformly applied on the hole-injecting/transporting layer 617 a in thefollowing steps.

Then, as shown in FIG. 32, a predetermined amount of the secondcomposition containing the light-emitting layer forming materialcorresponding to any one of colors (blue (B) in the example illustrationin FIG. 32) is implanted in the pixel area (the opening 619) as afunction liquid droplet. The second composition implanted in the pixelspreads over the hole-injecting/transporting layer 617 a and is filledin the opening 619. Meanwhile, in case where the second composition islanded outside the pixel area and on the upper surface 618 t of thebank-section 618, the liquid-repellent treatment has been previouslyapplied to the upper surface 618 t as described above, whereby thesecond composition is likely to roll in the opening 619.

Subsequently, by carrying out a drying step and so forth, when theejected second composition is dried, and nonpolar solvent contained inthe second composition is evaporated, the light-emitting layer 617 b isformed on the hole-injecting/transporting layer 617 a as shown in FIG.33. In the figure, the light-emitting layer 617 b corresponding to theblue color (B) is formed.

Likewise, with the function liquid droplet ejection head 71, as shown inFIG. 34, when the steps similar to those of the light-emitting layer 617b corresponding the above-described blue color (B) are sequentiallycarried out, the light-emitting layers 617 b corresponding to the otherred (R) and (G) colors are formed. Meanwhile, the light-emitting layers617 b is not limited to being formed in the foregoing example order andcan be formed in any order. For example, the order can be determineddepending on light-emitting layer forming materials. Also, an arrangingpattern of the three colors (R, G, and B) can be a stripe pattern, amosaic pattern, or a delta pattern, or the like.

The function layer 617 is formed on the pixel electrodes 613, that is,the hole-injecting/transporting layer 617 a and the light-emitting layer617 b are formed on the same in the manner as described above. Then, theprocess moves to the counter-electrode forming step S115.

In the counter-electrode forming step S115, as shown in FIG. 35, thecathode 604 (the counter electrode) is formed on the entire surfaces ofthe light-emitting layer 617 b and the organic bank layer 618 b, byvapor deposition, sputtering, chemical vapor deposition (CVD), or thelike. According to this embodiment, the cathode 604 is a laminate of acalcium layer and an aluminum layer, for example.

A protective layer composed of SiO₂, SiN, or the like is disposed abovethe cathode 604 if needed so as to serve as an antioxidant against Aland Ag film serving as electrodes.

After the cathode 604 is formed as described above, when othertreatments including a sealing treatment for sealing the upper part ofcathode 604 with a sealing member and a wiring treatment are carriedout, the display device 600 is obtained.

FIG. 36 is an exploded perspective view of an essential part of a plasmadisplay panel (PDP) device (hereinafter, simply referred to as a displaydevice 700), wherein a part of the display device 700 is cut away.

The display device 700 includes mutually opposing first and secondsubstrates 701 and 702, and a discharge display section 703 sandwichedbetween these substrates. The discharge display section 703 includes aplurality of discharge chambers 705. Of the plurality of dischargechambers 705, a set of red, green, and blue discharge chambers 705R,705G, and 705B is arranged so as to serve as a single pixel.

The first substrate 701 has address electrodes 706 formed on the uppersurface thereof in a stripe pattern at a predetermined interval, and adielectric layer 707 is formed so as to cover the upper surfaces of theaddress electrodes 706 and the first substrate 701. The dielectric layer707 has barriers 708 disposed thereon in a standing manner, each lyingbetween two of the address electrodes 706 and extending along thecorresponding address electrode 706. The barriers 708 include thoseextending along the address electrodes 706 as shown in the figure andthose (not illustrated) extending perpendicular to the addresselectrodes 706.

Thus, areas defined by the barriers 708 serve as the discharge chambers705.

The discharge chambers 705 have respective fluorescent members 709disposed therein. Each fluorescent substance 709 emits fluorescent lightof any one of colors red (R), green (G), and blue (B), and the red,green, and blue discharge chambers 705R, 705G, and 705B respectivelyhave red, green, and blue fluorescent members 709R, 709G, and 709Bdisposed at the bottoms thereof.

The second substrate 702 has a plurality of display electrodes 711disposed on the lower surface thereof, as shown in the figure, so as toextend in a direction perpendicular to the address electrodes 706, in astripe pattern at a predetermined interval, and a dielectric layer 712and a protective film 713 composed of MgO or the like are formed so asto cover these electrodes.

The first and second substrates 701 and 702 are bonded to each othersuch that the address electrodes 706 and the display electrodes 711 lieperpendicular to each other. The address electrodes 706 and the displayelectrodes 711 are connected to respective alternating power sources(not illustrated).

By energizing each of the electrodes 706 and 711, the fluorescentmembers 709 emit excitation light in the discharge display section 703so as to offer color display.

According to this embodiment, the address electrodes 706, the displayelectrodes 711, and the fluorescent members 709 can be formed with theliquid droplet ejection apparatus 1 shown in FIG. 1. A forming step ofthe address electrodes 706 of the first substrate 701 will be describedby way of example.

In this case, the following step is carried out in a state in which thefirst substrate 701 is placed on the setting table 41 of the liquiddroplet ejection apparatus 1.

Firstly, a function liquid droplet of liquid material (function liquid)containing a conductive-film wiring forming material is landed in anaddress-electrode forming area with the function liquid droplet ejectionheads 71. This liquid material contains conductive fine particlescomposed of metal or the like, dispersed in disperse media so as toserve as a conductive-film wiring forming material. This conductiveparticle can be a metal fine particle containing, for example, gold,silver, copper, palladium, nickel, a conductive polymer particle, or thelike.

When refilling of the liquid material in all address-electrode formingareas to be refilled is finished, by drying the ejected liquid materialand by evaporating dispersion media contained in the liquid material,the address electrodes 706 are formed.

Although the address electrodes 06 are formed by way of example in theabove description, the display electrodes 711 and the fluorescentmembers 709 can be also formed by undergoing the foregoing respectivesteps.

When the display electrodes 711 are formed, in the same fashion as theaddress electrodes 706, a function liquid droplet of a liquid material(function liquid) containing a conductive-film wiring forming materialis landed in a display-electrode forming area.

When the fluorescent members 709 are formed, function liquid droplets ofliquid materials (function liquid) containing fluorescent materialscorresponding to the respective colors (R, G, and B) are ejected by thefunction liquid droplet ejection heads 71 and landed in the dischargechambers 705 corresponding to the respective colors.

FIG. 37 is a sectional view of an essential part of an electron-emissiondevice (also called an FED device or an SED, hereinafter simply referredto as a display device 800).

The display device 800 generally includes mutually opposing first andsecond substrates 801 and 802 and a field-emission display section 803formed between these substrates. The field-emission display section 803is made up by a plurality of electron-emission sections 805 arranged ina matrix pattern.

The first substrate 801 has first element electrodes 806 a and secondelement electrodes 806 b formed on the upper surface thereof, making upcathode electrodes 806, so as to lie perpendicular to each other. Also,a conductive film 807 having a gap 808 formed therein is formed in asection defined by each first element electrode 806 a and each secondelement electrode 806 b. That is, the first element electrodes 806 a,the second element electrodes 806 b, and the conductive films 807 makeup the plurality of electron-emission sections 805. Each conductive film807 is composed of palladium oxide (PdO) or the like, and the gap 808 isformed, for example, by foaming after the conductive film 807 is formed.

The second substrate 802 has anode electrodes 809 on the lower surfacethereof so as to oppose the cathode electrodes 806. The anode electrodes809 have a bank section 811 formed in a latticed pattern on the lowersurface thereof. Downwardly-directed openings 812 encircled by the banksection 811 have fluorescent members 813 disposed therein so as tocorrespond to the respective electron-emission sections 805. Each of thefluorescent members 813 emits fluorescent light of any one of colors red(R), green (G), and blue (B), and red, green, and blue fluorescentmembers 813R, 813G, and 813B are disposed in the above-describedpredetermined pattern in the respective openings 812.

Then, the first and second substrates 801 and 802 formed as describedabove are bonded to each other having a fine gap therebetween. In thedisplay device 800, when an electron emitted from the first or secondelement electrode 806 a or 806 b making up the cathode hits upon thefluorescent member 813 formed on the under surface of the anodeelectrode 809 serving as an anode, through the conductive film 807 (thegap 808), the fluorescent member 813 emits excitation light, therebyoffering color display.

Also in this case, in the same fashion as in the other embodiments, thefirst and second element electrodes 806 a and 806 b, the conductive film807, and the anode electrodes 809 can be formed with the liquid dropletejection apparatus 1, and the fluorescent members 813R, 813G, and 813Bcorresponding to the respective colors can be also formed with theliquid droplet ejection apparatus 1.

Since the first and second element electrodes 806 a and 806 b, and theconductive film 807 have respective two dimensional shapes shown in FIG.38A, when these components are to be formed, a bank section BB is formedby lithography while sections in which the first and second elementelectrodes 806 a and 806 b and the conductive film 807 are to be formedare previously left in an unprocessed state as shown in FIG. 38B.Subsequently, the first and second element electrodes 806 a and 806 bare formed by an inkjet method with the liquid droplet ejectionapparatus 1 in depressions formed by the bank section, the solvent isdried so as to complete these components; and the conductive film 807 isthen formed by an inkjet method with the liquid droplet ejectionapparatus 1. When the conductive film 807 is completed, the bank sectionBB is removed by ashing, and the foregoing forming treatment is thencarried out. In the same fashion as in the organic EL device, the firstand second substrates 801 and 802, and the bank section 811 and BB andare preferably subjected to the lyophilic treatment and theliquid-repellent treatment, respectively.

By applying the liquid droplet ejection apparatus 1 shown in FIG. 1 toproduction of a variety of electrooptical devices, these devices can beeffectively manufactured.

What is claimed is:
 1. A method of drawing on a workpiece by ejectingfunctional liquid thereon while relatively scanning the workpiece and anejection head, the method comprising the steps of: a first scanning fordrawing in a plurality of first areas along a scanning direction; and asecond scanning for drawing in a second area between the plurality offirst areas drawn in by the first scanning.
 2. The method according toclaim 1 wherein a plurality of different functional liquids are ejected,and wherein the ejecting is performed on different areas per type offunctional liquid ejected in the first scanning.
 3. The method accordingto claim 2, wherein the second scanning further comprises ejecting adifferent functional liquid than that of the first scanning.
 4. Themethod according to claim 1, wherein the second scanning furthercomprises performing a plurality of scans.